bignumber.js/doc/API.html

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<div class="nav">
<a class='nav-title' href="#">bignumber.js</a>
<b> CONSTRUCTOR </b>
<ul>
<li><a href="#bignumber">BigNumber</a></li>
</ul>
<a href="#methods">Methods</a>
<ul>
<li><a href="#config">config</a></li>
<li>
<ul class="inset">
<li><a href="#decimal-places">DECIMAL_PLACES</a></li>
<li><a href="#rounding-mode" >ROUNDING_MODE</a></li>
<li><a href="#exponential-at">EXPONENTIAL_AT</a></li>
<li><a href="#range" >RANGE</a></li>
<li><a href="#errors" >ERRORS</a></li>
</ul>
</li>
</ul>
<a href="#constructor-properties">Properties</a>
<ul>
<li><a href="#round-up" >ROUND_UP</a></li>
<li><a href="#round-down" >ROUND_DOWN</a></li>
<li><a href="#round-ceil" >ROUND_CEIL</a></li>
<li><a href="#round-floor" >ROUND_FLOOR</a></li>
<li><a href="#round-half-up" >ROUND_HALF_UP</a></li>
<li><a href="#round-half-down" >ROUND_HALF_DOWN</a></li>
<li><a href="#round-half-even" >ROUND_HALF_EVEN</a></li>
<li><a href="#round-half-ceil" >ROUND_HALF_CEIL</a></li>
<li><a href="#round-half-floor">ROUND_HALF_FLOOR</a></li>
</ul>
<b> INSTANCE </b>
<a href="#prototype-methods">Methods</a>
<ul>
<li><a href="#abs" >absoluteValue</a></li>
<li><a href="#ceil" >ceil</a></li>
<li><a href="#floor" >floor</a></li>
<li><a href="#neg" >negated</a></li>
<li><a href="#sqrt" >squareRoot</a></li>
<li><a href="#isF" >isFinite</a></li>
<li><a href="#isNaN" >isNaN</a></li>
<li><a href="#isNeg" >isNegative</a></li>
<li><a href="#isZ" >isZero</a></li>
<li><a href="#cmp" >comparedTo</a></li>
<li><a href="#div" >dividedBy</a></li>
<li><a href="#minus" >minus</a></li>
<li><a href="#mod" >modulo</a></li>
<li><a href="#plus" >plus</a></li>
<li><a href="#times" >times</a></li>
<li><a href="#pow" >toPower</a></li>
<li><a href="#eq" >equals</a></li>
<li><a href="#gt" >greaterThan</a></li>
<li><a href="#gte" >greaterThanOrEqualTo</a></li>
<li><a href="#lt" >lessThan</a></li>
<li><a href="#lte" >lessThanOrEqualTo</a></li>
<li><a href="#toE" >toExponential</a></li>
<li><a href="#toF" >toFixed</a></li>
<li><a href="#toP" >toPrecision</a></li>
<li><a href="#toS" >toString</a></li>
<li><a href="#valueOf">valueOf</a></li>
<li><a href="#toFr" >toFraction</a></li>
<li><a href="#round" >round</a></li>
</ul>
<a href="#instance-properties">Properties</a>
<ul>
<li><a href="#coefficient">c : coefficient</a></li>
<li><a href="#exponent" >e : exponent</a></li>
<li><a href="#sign" >s : sign</a></li>
</ul>
<a href="#zero-nan-infinity">Zero, NaN &amp; Infinity</a>
<a href="#Errors">Errors</a>
<a class='end' href="#faq">FAQ</a>
</div>
<div class="container">
<h1>bignumber.js</h1>
<p>A Javascript library for arbitrary-precision arithmetic.</p>
<p>
<a href="https://github.com/MikeMcl/bignumber.js">Hosted on GitHub</a>.
</p>
<h2>API</h2>
<p>
In all examples below, <code>var</code> and semicolons are not shown, and
if a commented-out value is in quotes it means <code>toString</code> has
been called on the preceding expression.
</p>
<h3>CONSTRUCTOR</h3>
<h5 id="bignumber">
BigNumber<code class='inset'>BigNumber(value [, base]) &rArr;
<i>BigNumber</i>
</code>
</h5>
<dl>
<dt><code>value</code></dt>
<dd>
<i>number|string|BigNumber</i> : See <a href='#range'>RANGE</a> for
range.
</dd>
<dd>
A numeric value.
</dd>
<dd>
Legitimate values include <code>&plusmn;0</code>,
<code>&plusmn;Infinity</code> and <code>NaN</code>.
</dd>
<dd>
Values of type <em>number</em> with more than 15 significant digits are
considered invalid as calling <code>toString</code> or
<code>valueOf</code> on such numbers may not result in the intended
value.
</dd>
<dd>
There is no limit to the number of digits of a value of type
<em>string</em> (other than that of Javascript's maximum array size).
</dd>
<dd>
Decimal string values may be in exponential, as well as normal
(non-exponential) notation. Non-decimal values must be in normal
notation.
</dd>
<dd>
String values in hexadecimal literal form, e.g. '0xff', are invalid, and
string values in octal literal form will be interpreted as decimals,
e.g. '011' is 11, not 9.
</dd>
<dd>Values in any base may have fraction digits.</dd>
<dd>
In bases above 10, numerals above 9 are represented by lower-case
letters.
</dd>
</dl>
<dl>
<dt><code>base</code></dt>
<dd>
<i>number</i> : integer, <code>2</code> to <code>36</code> inclusive
</dd>
<dd>The base of <code>value</code>.</dd>
<dd>If <code>base</code> is omitted, or is <code>null</code> or undefined,
base 10 is assumed.</dd>
</dl>
<p>Returns a new instance of a BigNumber object.</p>
<p>
If a base is specified, the value is rounded according to
the current <a href='#decimal-places'><code>DECIMAL_PLACES</code></a> and
<a href='#rounding-mode'><code>ROUNDING_MODE</code></a> settings.
Usefully, this means the decimal places of a decimal value
passed to the constructor can be limited by explicitly specifying base 10.
</p>
<p>
See <a href='#Errors'>Errors</a> for the treatment of an invalid
<code>value</code> or <code>base</code>.
</p>
<pre>
x = new BigNumber(9) // '9'
y = new BigNumber(x) // '9'
BigNumber(435.345) // 'new' is optional
new BigNumber('5032485723458348569331745.33434346346912144534543')
new BigNumber('4.321e+4') // '43210'
new BigNumber('-735.0918e-430') // '-7.350918e-428'
new BigNumber(Infinity) // 'Infinity'
new BigNumber(NaN) // 'NaN'
new BigNumber('.5') // '0.5'
new BigNumber('+2') // '2'
new BigNumber(-10110100.1, 2) // '-180.5'
new BigNumber('123412421.234324', 5) // '607236.557696'
new BigNumber('ff.8', 16) // '255.5'
new BigNumber(9, 2)
// Throws 'not a base 2 number' if ERRORS is true, otherwise 'NaN'
new BigNumber(96517860459076817.4395)
// Throws 'number type has more than 15 significant digits'
// if ERRORS is true, otherwise '96517860459076820'
new BigNumber('blurgh')
// Throws 'not a number' if ERRORS is true, otherwise 'NaN'
BigNumber.config({DECIMAL_PLACES : 5})
new BigNumber(1.23456789) // '1.23456789'
new BigNumber(1.23456789, 10) // '1.23457'</pre>
<h4 id="methods">Methods</h4>
<p>
The <code>BigNumber</code> constructor has one added method,
<code>config</code>, which configures the library-wide settings for
arithmetic, formatting and errors.
</p>
<h5 id="config">
config<code class='inset'>config([settings]) &rArr; <i>object</i></code>
</h5>
<i>
Note: the settings can also be supplied as an argument list,
see below.
</i>
<dl>
<dt><code>settings</code></dt>
<dd><i>object</i></dd>
<dd>
An object that contains some or all of the following properties:
<dl>
<dt id="decimal-places"><code><b>DECIMAL_PLACES</b></code></dt>
<dd>
<i>number</i> : integer, <code>0</code> to <code>1e+9</code>
inclusive<br />
Default value: <code>20</code>
</dd>
<dd>
The <u>maximum</u> number of decimal places of the results of
division, square root and base conversion operations, and power
operations with negative exponents.<br />
I.e. aside from the base conversion which may be involved with any
method that accepts a base argument, the value is only relevant to
the <code>dividedBy</code>, <code>squareRoot</code> and
<code>toPower</code> methods.
</dd>
<dd>
<pre>BigNumber.config({ DECIMAL_PLACES : 5 })
BigNumber.config(5) // equivalent</pre>
</dd>
<dt id="rounding-mode"><code><b>ROUNDING_MODE</b></code></dt>
<dd>
<i>number</i> : integer, <code>0</code> to <code>8</code>
inclusive<br />
Default value: <code>4</code>
<a href="#h-up">(<code>ROUND_HALF_UP</code>)</a>
</dd>
<dd>
The rounding mode used in the above operations and by
<a href='#round'><code>round</code></a>,
<a href='#toE'><code>toExponential</code></a>,
<a href='#toF'><code>toFixed</code></a> and
<a href='#toP'><code>toPrecision</code></a>.
</dd>
<dd>
The modes are available as enumerated properties of the BigNumber
constructor.
</dd>
<dd>
<pre>BigNumber.config({ ROUNDING_MODE : 0 })
BigNumber.config(null, BigNumber.ROUND_UP) // equivalent</pre>
</dd>
<dt id="exponential-at"><code><b>EXPONENTIAL_AT</b></code></dt>
<dd>
<i>number</i> : integer, magnitude <code>0</code> to
<code>1e+9</code> inclusive, or<br />
<i>number</i>[] : [ integer -1e+9 to 0 inclusive, integer 0 to 1e+9
inclusive ]<br />
Default value: <code>[-7, 20]</code>
</dd>
<dd>
The exponent value(s) at which <code>toString</code> returns
exponential notation.
</dd>
<dd>
If a single number is assigned, the value is the exponent magnitude.
<br />
If an array of two numbers is assigned then the first number is the
negative exponent value at and beneath which exponential notation is
used, and the second number is the positive exponent value at and
above which the same.
</dd>
<dd>
For example, to emulate Javascript numbers in terms of the exponent
values at which they begin to use exponential notation, use
<code>[-7, 20]</code>.
</dd>
<dd>
<pre>BigNumber.config({ EXPONENTIAL_AT : 2 })
new BigNumber(12.3) // '12.3' e is only 1
new BigNumber(123) // '1.23e+2'
new BigNumber(0.123) // '0.123' e is only -1
new BigNumber(0.0123) // '1.23e-2'
BigNumber.config({ EXPONENTIAL_AT : [-7, 20] })
new BigNumber(123456789) // '123456789' e is only 8
new BigNumber(0.000000123) // '1.23e-7'
// Almost never return exponential notation:
BigNumber.config({ EXPONENTIAL_AT : 1e+9 })
// Always return exponential notation:
BigNumber.config({ EXPONENTIAL_AT : 0 })</pre>
</dd>
<dd>
Regardless of the value of <code>EXPONENTIAL_AT</code>, the
<code>toFixed</code> method will always return a value in
normal notation and the <code>toExponential</code> method will
always return a value in exponential form.
</dd>
<dd>
Calling <code>toString</code> with a base argument, e.g.
<code>toString(10)</code>, will also always return normal notation.
</dd>
<dt id="range"><code><b>RANGE</b></code></dt>
<dd>
<i>number</i> : integer, magnitude <code>1</code> to
<code>1e+9</code> inclusive, or<br />
<i>number</i>[] : [ integer -1e+9 to -1 inclusive, integer 1 to 1e+9
inclusive ]<br />
Default value: <code>[-1e+9, 1e+9]</code>
</dd>
<dd>
The exponent value(s) beyond which overflow to Infinity and
underflow to zero occurs.
</dd>
<dd>
If a single number is assigned, it is the maximum exponent
magnitude: values wth a positive exponent of greater magnitude
become Infinity and those with a negative exponent of
greater magnitude become zero.
<dd>
If an array of two numbers is assigned then the first number is the
negative exponent limit and the second number is the positive
exponent limit.
</dd>
<dd>
For example, to emulate Javascript numbers in terms of the exponent
values at which they become zero and Infinity, use
<code>[-324, 308]</code>.
</dd>
<dd>
<pre>BigNumber.config({ RANGE : 500 })
BigNumber.config().RANGE // [ -500, 500 ]
new BigNumber('9.999e499') // '9.999e+499'
new BigNumber('1e500') // 'Infinity'
new BigNumber('1e-499') // '1e-499'
new BigNumber('1e-500') // '0'
BigNumber.config({ RANGE : [-3, 4] })
new BigNumber(99999) // '99999' e is only 4
new BigNumber(100000) // 'Infinity' e is 5
new BigNumber(0.001) // '0.01' e is only -3
new BigNumber(0.0001) // '0' e is -4</pre>
</dd>
<dd>
The largest possible magnitude of a finite BigNumber is<br />
9.999...e+1000000000<br />
The smallest possible magnitude of a non-zero BigNumber is<br />
1e-1000000000
</dd>
<dt id="errors"><code><b>ERRORS</b></code></dt>
<dd>
<i>boolean/number</i> : <code>true, false, 1 or 0</code><br />
Default value: <code>true</code>
</dd>
<dd>
The value that determines whether BigNumber Errors are thrown.<br />
If <code>ERRORS</code> is false, this library will not throw errors.
</dd>
<dd>
See <a href='#Errors'>Errors</a>.
</dd>
<dd>
<pre>BigNumber.config({ ERRORS : false })</pre>
</dd>
</dl>
</dd>
</dl>
<p>
<br />Returns an object with the above properties and their current
values.
</p>
<p>
If the value to be assigned to any of the above properties is
<code>null</code> or undefined it is ignored. See
<a href='#Errors'>Errors</a> for the treatment of invalid values.
</p>
<pre>
BigNumber.config({
DECIMAL_PLACES : 40,
ROUNDING_MODE : BigNumber.ROUND_HALF_CEIL,
EXPONENTIAL_AT : [-10, 20],
RANGE : [-500, 500],
ERRORS : true
});
// Alternatively but equivalently:
BigNumber.config( 40, 7, [-10, 20], 500, 1 )
obj = BigNumber.config();
obj.ERRORS // true
obj.RANGE // [-500, 500]</pre>
<h4 id="constructor-properties">Properties</h4>
<p>
The library's enumerated rounding modes are stored as properties of the
constructor.<br />
They are not referenced internally by the library itself.
</p>
<p>
Rounding modes 0 to 6 (inclusive) are the same as those of Java's
BigDecimal class.
</p>
<table>
<tr>
<th>Property</th>
<th>Value</th>
<th>Description</th>
</tr>
<tr>
<td id="round-up"><b>ROUND_UP</b></td>
<td class='centre'>0</td>
<td>Rounds away from zero</td>
</tr>
<tr>
<td id="round-down"><b>ROUND_DOWN</b></td>
<td class='centre'>1</td>
<td>Rounds towards zero</td>
</tr>
<tr>
<td id="round-ceil"><b>ROUND_CEIL</b></td>
<td class='centre'>2</td>
<td>Rounds towards Infinity</td>
</tr>
<tr>
<td id="round-floor"><b>ROUND_FLOOR</b></td>
<td class='centre'>3</td>
<td>Rounds towards -Infinity</td>
</tr>
<tr>
<td id="round-half-up"><b>ROUND_HALF_UP</b></td>
<td class='centre'>4</td>
<td>
Rounds towards nearest neighbour.<br />
If equidistant, rounds away from zero
</td>
</tr>
<tr>
<td id="round-half-down"><b>ROUND_HALF_DOWN</b></td>
<td class='centre'>5</td>
<td>
Rounds towards nearest neighbour.<br />
If equidistant, rounds towards zero
</td>
</tr>
<tr>
<td id="round-half-even"><b>ROUND_HALF_EVEN</b></td>
<td class='centre'>6</td>
<td>
Rounds towards nearest neighbour.<br />
If equidistant, rounds towards even neighbour
</td>
</tr>
<tr>
<td id="round-half-ceil"><b>ROUND_HALF_CEIL</b></td>
<td class='centre'>7</td>
<td>
Rounds towards nearest neighbour.<br />
If equidistant, rounds towards Infinity
</td>
</tr>
<tr>
<td id="round-half-floor"><b>ROUND_HALF_FLOOR</b></td>
<td class='centre'>8</td>
<td>
Rounds towards nearest neighbour.<br />
If equidistant, rounds towards -Infinity
</td>
</tr>
</table>
<pre>
BigNumber.config({ ROUNDING_MODE : BigNumber.ROUND_CEIL })
BigNumber.config({ ROUNDING_MODE : 2 }) // equivalent</pre>
<h3>INSTANCE</h3>
<h4 id="prototype-methods">Methods</h4>
<p>
The methods inherited by a BigNumber instance from its constructor's
prototype object.
</p>
<p>
A BigNumber is immutable in the sense that it is not changed by its
methods.
</p>
<p>
The treatment of &plusmn;<code>0</code>, &plusmn;<code>Infinity</code> and
<code>NaN</code> is consistent with how Javascript treats these values.
</p>
<p>
Method names over 5 letters in length have a shorter alias (except
<code>valueOf</code>).<br />
Internally, the library always uses the shorter method names.
</p>
<h5 id="abs">
absoluteValue<code class='inset'>.abs() &rArr; <i>BigNumber</i></code>
</h5>
<p>
Returns a BigNumber whose value is the absolute value, i.e. the magnitude,
of this BigNumber.
</p>
<pre>
x = new BigNumber(-0.8)
y = x.absoluteValue() // '0.8'
z = y.abs() // '0.8'</pre>
<h5 id="ceil">
ceil<code class='inset'>.ceil() &rArr; <i>BigNumber</i></code>
</h5>
<p>
Returns a BigNumber whose value is the value of this BigNumber rounded to
a whole number in the direction of Infinity.
</p>
<pre>
x = new BigNumber(1.3)
x.ceil() // '2'
y = new BigNumber(-1.8)
y.ceil() // '-1'</pre>
<h5 id="floor">
floor<code class='inset'>.floor() &rArr;
<i>BigNumber</i></code>
</h5>
<p>
Returns a BigNumber whose value is the value of this BigNumber rounded to
a whole number in the direction of -Infinity.
</p>
<pre>
x = new BigNumber(1.8)
x.floor() // '1'
y = new BigNumber(-1.3)
y.floor() // '-2'</pre>
<h5 id="neg">
negated<code class='inset'>.neg() &rArr; <i>BigNumber</i></code>
</h5>
<p>
Returns a BigNumber whose value is the value of this BigNumber negated,
i.e. multiplied by -1.
</p>
<pre>
x = new BigNumber(1.8)
x.negated() // '-1.8'
y = new BigNumber(-1.3)
y.neg() // '1.3'</pre>
<h5 id="sqrt">
squareRoot<code class='inset'>.sqrt() &rArr; <i>BigNumber</i></code>
</h5>
<p>
Returns a BigNumber whose value is the square root of this BigNumber,
rounded according to the current
<a href='#decimal-places'><code>DECIMAL_PLACES</code></a> and
<a href='#rounding-mode'><code>ROUNDING_MODE</code></a> settings.
</p>
<pre>
x = new BigNumber(16)
x.squareRoot() // '4'
y = new BigNumber(3)
y.sqrt() // '1.73205080756887729353'</pre>
<h5 id="isF">
isFinite<code class='inset'>.isF() &rArr; <i>boolean</i></code>
</h5>
<p>
Returns <code>true</code> if the value of this BigNumber is a finite
number, otherwise returns <code>false</code>.<br />
The only possible non-finite values of a BigNumber are NaN, Infinity and
-Infinity.
</p>
<pre>
x = new BigNumber(1)
x.isFinite() // true
y = new BigNumber(Infinity)
y.isF() // false</pre>
<p>
Note: The native method <code>isFinite()</code> can be used if
<code>n &lt;= Number.MAX_VALUE</code>.
</p>
<h5 id="isNaN">
isNaN<code class='inset'>.isNaN() &rArr; <i>boolean</i></code>
</h5>
<p>
Returns <code>true</code> if the value of this BigNumber is NaN, otherwise
returns <code>false</code>.<br />
</p>
<pre>
x = new BigNumber(NaN)
x.isNaN() // true
y = new BigNumber('Infinity')
y.isNaN() // false</pre>
<p>
Note: The native method <code>isNaN()</code> can also be used.
</p>
<h5 id="isNeg">
isNegative<code class='inset'>.isNeg() &rArr; <i>boolean</i></code>
</h5>
<p>
Returns <code>true</code> if the value of this BigNumber is negative,
otherwise returns <code>false</code>.<br />
</p>
<pre>
x = new BigNumber(-0)
x.isNegative() // true
y = new BigNumber(2)
y.isNeg // false</pre>
<p>
Note: <code>n &lt; 0</code> can be used if
<code>n &lt;= -Number.MIN_VALUE</code>.
</p>
<h5 id="isZ">
isZero<code class='inset'>.isZ() &rArr; <i>boolean</i></code>
</h5>
<p>
Returns <code>true</code> if the value of this BigNumber is zero or minus
zero, otherwise returns <code>false</code>.<br />
</p>
<pre>
x = new BigNumber(-0)
x.isZero() && x.isNeg() // true
y = new BigNumber(Infinity)
y.isZ() // false</pre>
<p>
Note: <code>n == 0</code> can be used if
<code>n &gt;= Number.MIN_VALUE</code>.
</p>
<h5 id="cmp">
comparedTo<code class='inset'>.cmp(n [, base]) &rArr; <i>number</i></code>
</h5>
<p>
<code>n</code> : <i>number|string|BigNumber</i><br />
<code>base</code> : <i>number</i><br />
<i>
See <a href="#bignumber">constructor</a> for further parameter details.
</i>
</p>
<table>
<tr>
<th>Returns</th>
<th colspan=2>&nbsp;</th>
</tr>
<tr>
<td class='centre'>1</td>
<td>
If the value of this BigNumber is greater than the value of <code>n</code>
</td>
</tr>
<tr>
<td class='centre'>-1</td>
<td>
If the value of this BigNumber is less than the value of <code>n</code>
</td>
</tr>
<tr>
<td class='centre'>0</td>
<td>If this BigNumber and <code>n</code> have the same value</td>
</tr>
<tr>
<td class='centre'>null</td>
<td>
if the value of either this BigNumber or <code>n</code> is
<code>NaN</code>
</td>
</tr>
</table>
<pre>
x = new BigNumber(Infinity)
y = new BigNumber(5)
x.comparedTo(y) // 1
x.comparedTo(x.minus(1)) // 0
y.cmp(NaN) // null
y.cmp('110', 2) // -1</pre>
<h5 id="div">
dividedBy<code class='inset'>.div(n [, base]) &rArr;
<i>BigNumber</i></code>
</h5>
<p>
<code>n</code> : <i>number|string|BigNumber</i><br />
<code>base</code> : <i>number</i><br />
<i>See <a href="#bignumber">constructor</a> for further parameter details.
</i>
</p>
<p>
Returns a BigNumber whose value is the value of this BigNumber divided by
<code>n</code>, rounded according to the current
<a href='#decimal-places'><code>DECIMAL_PLACES</code></a> and
<a href='#rounding-mode'><code>ROUNDING_MODE</code></a> settings.
</p>
<pre>
x = new BigNumber(355)
y = new BigNumber(113)
x.dividedBy(y) // '3.14159292035398230088'
x.div(5) // '71'
x.div(47, 16) // '5'</pre>
<h5 id="minus">
minus<code class='inset'>.minus(n [, base]) &rArr; <i>BigNumber</i></code>
</h5>
<p>
<code>n</code> : <i>number|string|BigNumber</i><br />
<code>base</code> : <i>number</i><br />
<i>See <a href="#bignumber">constructor</a> for further parameter details.
</i>
</p>
<p>
Returns a BigNumber whose value is the value of this BigNumber minus
<code>n</code>.
</p>
<pre>
0.3 - 0.1 // 0.19999999999999998
x = new BigNumber(0.3)
x.minus(0.1) // '0.2'
x.minus(0.6, 20) // '0'</pre>
<h5 id="mod">
modulo<code class='inset'>.mod(n [, base]) &rArr; <i>BigNumber</i></code>
</h5>
<p>
<code>n</code> : <i>number|string|BigNumber</i><br />
<code>base</code> : <i>number</i><br />
<i>See <a href="#bignumber">constructor</a> for further parameter details.
</i>
</p>
<p>
Returns a BigNumber whose value is the value of this BigNumber modulo
<code>n</code>, i.e. the integer remainder of dividing this BigNumber by
<code>n</code>.
</p>
<p>
The result will have the same sign as this BigNumber, and it will match
that of Javascript's % operator (within the limits of its precision) and
BigDecimal's remainder method.
</p>
<pre>
1 % 0.9 // 0.09999999999999998
x = new BigNumber(1)
x.modulo(0.9) // '0.1'
y = new BigNumber(33)
y.mod('a', 33) // '3'</pre>
<h5 id="plus">
plus<code class='inset'>.plus(n [, base]) &rArr; <i>BigNumber</i></code>
</h5>
<p>
<code>n</code> : <i>number|string|BigNumber</i><br />
<code>base</code> : <i>number</i><br />
<i>See <a href="#bignumber">constructor</a> for further parameter details.
</i>
</p>
<p>
Returns a BigNumber whose value is the value of this BigNumber plus
<code>n</code>.
</p>
<pre>
0.1 + 0.2 // 0.30000000000000004
x = new BigNumber(0.1)
y = x.plus(0.2) // '0.3'
BigNumber(0.7).plus(x).plus(y) // '1'
x.plus('0.1', 8) // '0.225'</pre>
<h5 id="times">
times<code class='inset'>.times(n [, base]) &rArr; <i>BigNumber</i></code>
</h5>
<p>
<code>n</code> : <i>number|string|BigNumber</i><br />
<code>base</code> : <i>number</i><br />
<i>See <a href="#bignumber">constructor</a> for further parameter details.
</i>
</p>
<p>
Returns a BigNumber whose value is the value of this BigNumber times
<code>n</code>.
</p>
<pre>
0.6 * 3 // 1.7999999999999998
x = new BigNumber(0.6)
y = x.times(3) // '1.8'
BigNumber('7e+500').times(y) // '1.26e+501'
x.times('-a', 16) // '-6'</pre>
<h5 id="pow">
toPower<code class='inset'>.pow(exp) &rArr; <i>BigNumber</i></code>
</h5>
<p>
<code>exp</code> : <i>number</i> : integer, -1e+6 to 1e+6 inclusive
</p>
<p>
Returns a BigNumber whose value is the value of this BigNumber raised to
the power <code>exp</code>.
</p>
<p>
If <code>exp</code> is negative the result is rounded according to the
current <a href='#decimal-places'><code>DECIMAL_PLACES</code></a> and
<a href='#rounding-mode'><code>ROUNDING_MODE</code></a> settings.
</p>
<p>
If <code>exp</code> is not an integer or is out of range:
</p>
<p class='inset'>
If <code>ERRORS</code> is <code>true</code> a BigNumber
Error is thrown,<br />
else if <code>exp</code> is greater than 1e+6, it is interpreted as
<code>Infinity</code>;<br />
else if <code>exp</code> is less than -1e+6, it is interpreted as
<code>-Infinity</code>;<br />
else if <code>exp</code> is otherwise a number, it is truncated to an
integer;<br />
else it is interpreted as <code>NaN</code>.
</p>
<p>
Note: High value exponents may cause this method to be slow to return.
</p>
<pre>
Math.pow(0.7, 2) // 0.48999999999999994
x = new BigNumber(0.7)
x.toPower(2) // '0.49'
BigNumber(3).pow(-2) // '0.11111111111111111111'
new BigNumber(123.456).toPower(1000).toString().length // 5099
new BigNumber(2).pow(1e+6) // Time taken (Node.js): 9 minutes 34 secs.</pre>
<h5 id="eq">
equals<code class='inset'>.eq(n [, base]) &rArr; <i>boolean</i></code>
</h5>
<p>
<code>n</code> : <i>number|string|BigNumber</i><br />
<code>base</code> : <i>number</i><br />
<i>See <a href="#bignumber">constructor</a> for further parameter details.
</i>
</p>
<p>
Returns <code>true</code> if the value of this BigNumber equals the value
of <code>n</code>, otherwise returns <code>false</code>.<br />
As with Javascript, NaN does not equal NaN.
<br />Note : This method uses the <code>comparedTo</code> method
internally.
</p>
<pre>
0 === 1e-324 // true
x = new BigNumber(0)
x.equals('1e-324') // false
BigNumber(-0).eq(x) // true ( -0 === 0 )
BigNumber(255).eq('ff', 16) // true
y = new BigNumber(NaN)
y.equals(NaN) // false</pre>
<h5 id="gt">
greaterThan<code class='inset'>.gt(n [, base]) &rArr;
<i>boolean</i></code>
</h5>
<p>
<code>n</code> : <i>number|string|BigNumber</i><br />
<code>base</code> : <i>number</i><br />
<i>See <a href="#bignumber">constructor</a> for further parameter details.
</i>
</p>
<p>
Returns <code>true</code> if the value of this BigNumber is greater than
the value of <code>n</code>, otherwise returns <code>false</code>.<br />
Note : This method uses the <code>comparedTo</code> method internally.
</p>
<pre>
0.1 &gt; (0.3 - 0.2) // true
x = new BigNumber(0.1)
x.greaterThan(BigNumber(0.3).minus(0.2)) // false
BigNumber(0).gt(x) // false
BigNumber(11, 3).gt(11.1, 2) // true</pre>
<h5 id="gte">
greaterThanOrEqualTo<code class='inset'>.gte(n [, base]) &rArr;
<i>boolean</i></code>
</h5>
<p>
<code>n</code> : <i>number|string|BigNumber</i><br />
<code>base</code> : <i>number</i><br />
<i>See <a href="#bignumber">constructor</a> for further parameter details.
</i>
</p>
<p>
Returns <code>true</code> if the value of this BigNumber is greater than
or equal to the value of <code>n</code>, otherwise returns
<code>false</code>.<br />
Note : This method uses the <code>comparedTo</code> method internally.
</p>
<pre>
(0.3 - 0.2) &gt;= 0.1 // false
x = new BigNumber(0.3).minus(0.2)
x.greaterThanOrEqualTo(0.1) // true
BigNumber(1).gte(x) // true
BigNumber(10, 18).gte('i', 36) // true</pre>
<h5 id="lt">
lessThan<code class='inset'>.lt(n [, base]) &rArr; <i>boolean</i></code>
</h5>
<p>
<code>n</code> : <i>number|string|BigNumber</i><br />
<code>base</code> : <i>number</i><br />
<i>See <a href="#bignumber">constructor</a> for further parameter details.
</i>
</p>
<p>
Returns <code>true</code> if the value of this BigNumber is less than the
value of <code>n</code>, otherwise returns <code>false</code>.<br />
Note : This method uses the <code>comparedTo</code> method internally.
</p>
<pre>
(0.3 - 0.2) &lt; 0.1 // true
x = new BigNumber(0.3).minus(0.2)
x.lessThan(0.1) // false
BigNumber(0).lt(x) // true
BigNumber(11.1, 2).lt(11, 3) // true</pre>
<h5 id="lte">
lessThanOrEqualTo<code class='inset'>.lte(n [, base]) &rArr;
<i>boolean</i></code>
</h5>
<p>
<code>n</code> : <i>number|string|BigNumber</i><br />
<code>base</code> : <i>number</i><br />
<i>See <a href="#bignumber">constructor</a> for further parameter details.
</i>
</p>
<p>
Returns <code>true</code> if the value of this BigNumber is less than or
equal to the value of <code>n</code>, otherwise returns
<code>false</code>.<br />
Note : This method uses the <code>comparedTo</code> method internally.
</p>
<pre>
0.1 &lt;= (0.3 - 0.2) // false
x = new BigNumber(0.1)
x.lessThanOrEqualTo(BigNumber(0.3).minus(0.2)) // true
BigNumber(-1).lte(x) // true
BigNumber(10, 18).lte('i', 36) // true</pre>
<h5 id="toE">
toExponential<code class='inset'>.toE([decimal_places]) &rArr;
<i>string</i></code>
</h5>
<p>
<code>decimal_places</code> : <i>number</i> : integer, 0 to 1e+9 inclusive
</p>
<p>
Returns a string representing the value of this BigNumber in exponential
notation to the specified decimal places, i.e with one digit before the
decimal point and <code>decimal_places</code> digits after it. If rounding
is necessary, the current
<a href='#rounding-mode'><code>ROUNDING_MODE</code></a> is used.
</p>
<p>
If the value of this BigNumber in exponential notation has fewer fraction
digits then is specified by <code>decimal_places</code>, the return value
will be appended with zeros accordingly.
</p>
<p>
If <code>decimal_places</code> is omitted, or is <code>null</code> or
undefined, the number of digits after the decimal point defaults to the
minimum number of digits necessary to represent the value exactly.
</p>
<p>
See <a href='#Errors'>Errors</a> for the treatment of other
non-integer or out of range <code>decimal_places</code> values.
</p>
<pre>
x = 45.6
y = new BigNumber(x)
x.toExponential() // '4.56e+1'
y.toExponential() // '4.56e+1'
x.toExponential(0) // '5e+1'
y.toE(0) // '5e+1'
x.toExponential(1) // '4.6e+1'
y.toE(1) // '4.6e+1'
x.toExponential(3) // '4.560e+1'
y.toE(3) // '4.560e+1'</pre>
<h5 id="toF">
toFixed<code class='inset'>.toF([decimal_places]) &rArr;
<i>string</i></code>
</h5>
<p>
<code>decimal_places</code> : <i>number</i> : integer, 0 to 1e+9 inclusive
</p>
<p>
Returns a string representing the value of this BigNumber in normal
notation to the specified fixed number of decimal places, i.e. with
<code>decimal_places</code> digits after the decimal point. If rounding is
necessary, the current
<a href='#rounding-mode'><code>ROUNDING_MODE</code></a> setting is used.
</p>
<p>
If the value of this BigNumber in normal notation has fewer fraction
digits then is specified by <code>decimal_places</code>, the return value
will be appended with zeros accordingly.
</p>
<p>
Unlike <code>Number.prototype.toFixed</code>, which returns
exponential notation if a number is greater or equal to 10<sup>21</sup>,
this method will always return normal notation.
</p>
<p>
If <code>decimal_places</code> is omitted, or is <code>null</code> or
undefined, then the return value is the same as <code>n.toString()</code>.
This is also unlike <code>Number.prototype.toFixed</code>, which returns
the value to zero decimal places.
</p>
<p>
See <a href='#Errors'>Errors</a> for the treatment of other
non-integer or out of range <code>decimal_places</code> values.
</p>
<pre>
x = 45.6
y = new BigNumber(x)
x.toFixed() // '46'
y.toFixed() // '45.6'
y.toF(0) // '46'
x.toFixed(3) // '45.600'
y.toF(3) // '45.600'</pre>
<h5 id="toP">
toPrecision<code class='inset'>.toP([significant_figures]) &rArr;
<i>string</i></code>
</h5>
<p>
<code>significant_figures</code> : <i>number</i> : integer, 1 to 1e+9
inclusive
</p>
<p>
Returns a string representing the value of this BigNumber to the
specified number of significant digits. If rounding is necessary, the
current <a href='#rounding-mode'><code>ROUNDING_MODE</code></a> setting is
used.
</p>
<p>
If <code>significant_figures</code> is less than the number of digits
necessary to represent the integer part of the value in normal notation,
then exponential notation is used.
</p>
<p>
If <code>significant_figures</code> is omitted, or is <code>null</code> or
undefined, then the return value is the same as <code>n.toString()</code>.
</p>
<p>
See <a href='#Errors'>Errors</a> for the treatment of other
non-integer or out of range <code>significant_figures</code> values.
</p>
<pre>
x = 45.6
y = new BigNumber(x)
x.toPrecision() // '45.6'
y.toPrecision() // '45.6'
x.toPrecision(1) // '5e+1'
y.toP(1) // '5e+1'
x.toPrecision(5) // '45.600'
y.toP(5) // '45.600'</pre>
<h5 id="toS">
toString<code class='inset'>.toS([base]) &rArr; <i>string</i></code>
</h5>
<p>
<code>base</code> : <i>number</i> : integer, 2 to 36 inclusive
</p>
<p>
Returns a string representing the value of this BigNumber in the specified
base, or base 10 if <code>base</code> is omitted. Like
<code>Number.toString</code>, in bases above 10, numerals above 9 are
represented by lower-case letters.
</p>
<p>
If a base is specified the value is rounded according to the current
<a href='#decimal-places'><code>DECIMAL_PLACES</code></a>
and <a href='#rounding-mode'><code>ROUNDING_MODE</code></a> settings.
</p>
<p>
If a base is not specified, and this BigNumber has a positive
exponent that is equal to or greater than the positive component of the
current <a href="#exponential-at"><code>EXPONENTIAL_AT</code></a> setting,
or a negative exponent equal to or less than the negative component of the
setting, then exponential notation is returned.
</p>
<p>
If <code>base</code> is <code>null</code> or undefined it is ignored.
<br />
See <a href='#Errors'>Errors</a> for the treatment of other non-integer or
out of range <code>base</code> values.
</p>
<pre>
x = new BigNumber(750000)
x.toString() // '750000'
BigNumber.config({ EXPONENTIAL_AT : 5 })
x.toString() // '7.5e+5'
y = new BigNumber(362.875)
y.toString(2) // '101101010.111'
y.toString(9) // '442.77777777777777777778'
y.toString(32) // 'ba.s'
BigNumber.config({ DECIMAL_PLACES : 4 });
z = new BigNumber('1.23456789')
z.toString() // '1.23456789'
z.toString(10) // '1.2346'</pre>
<h5 id="valueOf">
valueOf<code class='inset'>.valueOf() &rArr; <i>string</i></code>
</h5>
<p>
As <code>toString</code>, but does not accept a base argument.
</p>
<pre>
x = new BigNumber('1.777e+457')
x.valueOf() // '1.777e+457'</pre>
<h5 id="toFr">
toFraction<code class='inset'>.toFr([max_denominator]) &rArr;
<i>[string, string]</i></code>
</h5>
<p>
<code>max_denominator</code> : <i>number|string|BigNumber</i> :
integer &gt;= 1 and &lt; Infinity
</p>
<p>
Returns a string array representing the value of this BigNumber as a
simple fraction with an integer numerator and an integer denominator. The
denominator will be a positive non-zero value less than or equal to
<code>max_denominator</code>.
</p>
<p>
If a maximum denominator is not specified, or is <code>null</code> or
undefined, the denominator will be the lowest value necessary to represent
the number exactly.
</p>
<p>
See <a href='#Errors'>Errors</a> for the treatment of other non-integer or
out of range <code>max_denominator</code> values.
</p>
<pre>
x = new BigNumber(1.75)
x.toFraction() // '7, 4'
pi = new BigNumber('3.14159265358')
pi.toFr() // '157079632679,50000000000'
pi.toFr(100000) // '312689, 99532'
pi.toFr(10000) // '355, 113'
pi.toFr(100) // '311, 99'
pi.toFr(10) // '22, 7'
pi.toFr(1) // '3, 1'</pre>
<h5 id="round">
round<code class='inset'>.round([decimal_places [, rounding_mode]])
&rArr; <i>BigNumber</i></code>
</h5>
<p>
<code>decimal_places</code> : <i>number</i> : integer, 0 to 1e+9 inclusive
<br />
<code>rounding_mode</code> : <i>number</i> : integer, 0 to 8 inclusive
</p>
<p>
Returns a BigNumber whose value is the value of this BigNumber rounded by
the specified <code>rounding_mode</code> to a maximum of
<code>decimal_places</code> digits after the decimal point.
</p>
<p>
if <code>decimal_places</code> is omitted, or is <code>null</code> or
undefined, the return value is <code>n</code> rounded to a whole number.
</p>
<p>
if <code>rounding_mode</code> is omitted, or is <code>null</code> or
undefined, the current
<a href='#rounding-mode'><code>ROUNDING_MODE</code></a> setting is used.
</p>
<p>
See <a href='#Errors'>Errors</a> for the treatment of other
non-integer or out of range <code>decimal_places</code> or
<code>rounding_mode</code> values.
</p>
<pre>
x = 1234.56
Math.round(x) // 1235
y = new BigNumber(x)
y.round() // '1235'
y.round(1) // '1234.6'
y.round(2) // '1234.56'
y.round(10) // '1234.56'
y.round(0, 1) // '1234'
y.round(0, 6) // '1235'
y.round(1, 1) // '1234.5'
y.round(1, BigNumber.ROUND_HALF_EVEN) // '1234.6'
y // '1234.56'</pre>
<h4 id="instance-properties">Properties</h4>
<p>
A BigNumber is an object with three properties:
</p>
<table>
<tr>
<th>Property</th>
<th>Description</th>
<th>Type</th>
<th>Value</th>
</tr>
<tr>
<td class='centre' id='coefficient'><b>c</b></td>
<td>coefficient<sup>*</sup></td>
<td><i>number</i><code>[]</code></td>
<td> Array of single digits</td>
</tr>
<tr>
<td class='centre' id='exponent'><b>e</b></td>
<td>exponent</td>
<td><i>number</i></td>
<td>Integer, -1e+9 to 1e+9 inclusive</td>
</tr>
<tr>
<td class='centre' id='sign'><b>s</b></td>
<td>sign</td>
<td><i>number</i></td>
<td>-1 or 1</td>
</tr>
</table>
<p><sup>*</sup>significand</p>
<p>
The value of any of the three properties may also be <code>null</code>.
</p>
<p>
The value of a BigNumber is stored in a normalised decimal floating point
format which corresponds to the value's <code>toExponential</code> form,
with the decimal point to be positioned after the most significant
(left-most) digit of the coefficient.
</p>
<p>
Note that, as with Javascript numbers, the original exponent and
fractional trailing zeros are not preserved.
</p>
<pre>x = new BigNumber(0.123) // '0.123'
x.toExponential() // '1.23e-1'
x.c // '1,2,3'
x.e // -1
x.s // 1
y = new Number(-123.4567000e+2) // '-12345.67'
y.toExponential() // '-1.234567e+4'
z = new BigNumber('-123.4567000e+2') // '-12345.67'
z.toExponential() // '-1.234567e+4'
z.c // '1,2,3,4,5,6,7'
z.e // 4
z.s // -1</pre>
<p>
A BigNumber is mutable in the sense that the value of its properties can
be changed.<br />
For example, to rapidly shift a value by a power of 10:
</p>
<pre>
x = new BigNumber('1234.000') // '1234'
x.toExponential() // '1.234e+3'
x.c // '1,2,3,4'
x.e // 3
x.e = -5
x // '0.00001234'</pre>
<p>
If changing the coefficient array directly, which is not recommended, be
careful to avoid leading or trailing zeros (unless zero itself is being
represented).
</p>
<h4 id="zero-nan-infinity">Zero, NaN and Infinity</h4>
<p>
The table below shows how &plusmn;0, NaN and &plusmn;Infinity are stored.
</p>
<table>
<tr>
<th> </th>
<th class='centre'>c</th>
<th class='centre'>e</th>
<th class='centre'>s</th>
</tr>
<tr>
<td>&plusmn;0</td>
<td><code>[0]</code></td>
<td><code>0</code></td>
<td><code>&plusmn;1</code></td>
</tr>
<tr>
<td>NaN</td>
<td><code>null</code></td>
<td><code>null</code></td>
<td><code>null</code></td>
</tr>
<tr>
<td>&plusmn;Infinity</td>
<td><code>null</code></td>
<td><code>null</code></td>
<td><code>&plusmn;1</code></td>
</tr>
</table>
<pre>
x = new Number(-0) // 0
1 / x == -Infinity // true
y = new BigNumber(-0) // '0'
y.c // '0' ( [0].toString() )
y.e // 0
y.s // -1</pre>
<h4 id='Errors'>Errors</h4>
<p>
The table below shows the BigNumber Errors that may be thrown if
<code>ERRORS</code> is <code>true</code>, and what happens if
<code>ERRORS</code> is <code>false</code>.
</p>
<table class='error-table'>
<tr>
<th>Method(s)</th>
<th>ERRORS : true<br />Throw BigNumber Error</th>
<th>ERRORS : false<br />Action on invalid argument</th>
</tr>
<tr>
<td rowspan=5><code>
BigNumber<br />
comparedTo<br />
dividedBy<br />
equals<br />
greaterThan<br />
greaterThanOrEqualTo<br />
lessThan<br />
lessThanOrEqualTo<br />
minus<br />
mod<br />
plus<br />
times</code></td>
<td>number type has more than<br />15 significant digits</td>
<td>Accept.</td>
</tr>
<tr>
<td>not a base... number</td>
<td>Substitute <code>NaN</code>.</td>
</tr>
<tr>
<td>base not an integer</td>
<td>Truncate to integer.<br />Ignore if not a number.</td>
</tr>
<tr>
<td>base out of range</td>
<td>Ignore.</td>
</tr>
<tr>
<td>not a number<sup>*</sup></td>
<td>Substitute <code>NaN</code>.</td>
</tr>
<tr>
<td rowspan=9><code>config</code></td>
<td><code>DECIMAL_PLACES</code> not an integer</td>
<td>Truncate to integer.<br />Ignore if not a number.</td>
</tr>
<tr>
<td><code>DECIMAL_PLACES</code> out of range</td>
<td>Ignore.</td>
</tr>
<tr>
<td><code>ROUNDING_MODE</code> not an integer</td>
<td>Truncate to integer.<br />Ignore if not a number.</td>
</tr>
<tr>
<td><code>ROUNDING_MODE</code> out of range</td>
<td>Ignore.</td>
</tr>
<tr>
<td>
<code>EXPONENTIAL_AT</code> not an integer<br />
or not [integer, integer]
</td>
<td>Truncate to integer(s).<br />Ignore if not number(s).</td>
</tr>
<tr>
<td>
<code>EXPONENTIAL_AT</code> out of range<br />
or not [negative, positive]
</td>
<td>Ignore.</td>
</tr>
<tr>
<td>
<code>RANGE</code> not a non-zero integer<br />
or not [integer, integer]
</td>
<td> Truncate to integer(s).<br />Ignore if zero or not number(s).</td>
</tr>
<tr>
<td>
<code>RANGE</code> out of range<br />
or not [negative, positive]
</td>
<td>Ignore.</td>
</tr>
<tr>
<td>
<code>ERRORS</code> not a boolean<br />
or binary digit
</td>
<td>Ignore.</td>
</tr>
<tr>
<td rowspan=2><code>toPower</code></td>
<td>exponent not an integer</td>
<td>Truncate to integer.<br />Substitute <code>NaN</code> if not a number.</td>
</tr>
<tr>
<td>exponent out of range</td>
<td>Substitute <code>&plusmn;Infinity</code>.
</td>
</tr>
<tr>
<td rowspan=4><code>round</code></td>
<td>decimal places not an integer</td>
<td>Truncate to integer.<br />Ignore if not a number.</td>
</tr>
<tr>
<td>decimal places out of range</td>
<td>Ignore.</td>
</tr>
<tr>
<td>mode not an integer</td>
<td>Truncate to integer.<br />Ignore if not a number.</td>
</tr>
<tr>
<td>mode out of range</td>
<td>Ignore.</td>
</tr>
<tr>
<td rowspan=2><code>toExponential</code></td>
<td>decimal places not an integer</td>
<td>Truncate to integer.<br />Ignore if not a number.</td>
</tr>
<tr>
<td>decimal places out of range</td>
<td>Ignore.</td>
</tr>
<tr>
<td rowspan=2><code>toFixed</code></td>
<td>decimal places not an integer</td>
<td>Truncate to integer.<br />Ignore if not a number.</td>
</tr>
<tr>
<td>decimal places out of range</td>
<td>Ignore.</td>
</tr>
<tr>
<td rowspan=2><code>toFraction</code></td>
<td>max denominator not an integer</td>
<td>Truncate to integer.<br />Ignore if not a number.</td>
</tr>
<tr>
<td>max denominator out of range</td>
<td>Ignore.</td>
</tr>
<tr>
<td rowspan=2><code>toPrecision</code></td>
<td>precision not an integer</td>
<td>Truncate to integer.<br />Ignore if not a number.</td>
</tr>
<tr>
<td>precision out of range</td>
<td>Ignore.</td>
</tr>
<tr>
<td rowspan=2><code>toString</code></td>
<td>base not an integer</td>
<td>Truncate to integer.<br />Ignore if not a number.</td>
</tr>
<tr>
<td>base out of range</td>
<td>Ignore.</td>
</tr>
</table>
<p>
<sup>*</sup>No error is thrown if the value is <code>NaN</code> or 'NaN'
</p>
<p>
The message of a BigNumber Error will also contain the name of the
method from which the error originated.
</p>
<p>
To determine if an exception is a BigNumber Error:
</p>
<pre>
try {
// do something with BigNumbers
} catch (e) {
if (e.name == 'BigNumber Error') {
// do something
}
}</pre>
<h4 id='faq'>FAQ</h4>
<h6>Why are trailing fractional zeros removed from BigNumbers?</h6>
<p>
Many arbitrary-precision libraries retain trailing fractional zeros as
they can indicate the precision of a value. This can be useful but the
results of arithmetic operations can be misleading.
</p>
<pre>
x = new BigDecimal("1.0")
y = new BigDecimal("1.1000")
z = x.add(y) // 2.1000
x = new BigDecimal("1.20")
y = new BigDecimal("3.45000")
z = x.multiply(y) // 4.1400000</pre>
<p>
To specify the precision of a value is to specify that the value lies
within a certain range.
</p>
<p>
In the first example, <code>x</code> has a value of 1.0. The trailing zero
shows the precision of the value, implying that it is in the range 0.95 to
1.05. Similarly, the precision indicated by the trailing zeros of
<code>y</code> indicates that the value is in the range 1.09995 to
1.10005. If we add the two lowest values in the ranges we get 0.95 +
1.09995 = 2.04995 and if we add the two highest values we get 1.05 +
1.10005 = 2.15005, so the range of the result of the addition implied by
the precision of its operands is 2.04995 to 2.15005. The result given by
BigDecimal of 2.1000 however, indicates that the value is in the range
2.09995 to 2.10005 and therefore the precision implied by its trailing
zeros is misleading.
</p>
<p>
In the second example, the true range is 4.122744 to 4.157256 yet the
BigDecimal answer of 4.1400000 indicates a range of 4.13999995 to
4.14000005. Again, the precision implied by the trailing zeros is
misleading.
</p>
<p>
This library, like Javascript and most calculators, does not
retain trailing fractional zeros. Instead, the <code>toExponential</code>,
<code>toFixed</code> and <code>toPrecision</code> methods enable trailing
zeros to be added if and when required.
</p>
<br />
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