diff --git a/bignumber.js b/bignumber.js
index e118ba8..5ebb5da 100644
--- a/bignumber.js
+++ b/bignumber.js
@@ -728,7 +728,7 @@
 
                         if ( !d ) {
                             ++e;
-                            xc.unshift(1);
+                            xc = [1].concat(xc);
                         }
                     }
                 }
@@ -766,7 +766,7 @@
                     x[i] = temp % base;
                 }
 
-                if (carry) x.unshift(carry);
+                if (carry) x = [carry].concat(x);
 
                 return x;
             }
@@ -869,7 +869,7 @@
                     // Add zeros to make remainder as long as divisor.
                     for ( ; remL < yL; rem[remL++] = 0 );
                     yz = yc.slice();
-                    yz.unshift(0);
+                    yz = [0].concat(yz);
                     yc0 = yc[0];
                     if ( yc[1] >= base / 2 ) yc0++;
                     // Not necessary, but to prevent trial digit n > base, when using base 3.
@@ -940,7 +940,7 @@
                                 prodL = prod.length;
                             }
 
-                            if ( prodL < remL ) prod.unshift(0);
+                            if ( prodL < remL ) prod = [0].concat(prod);
 
                             // Subtract product from remainder.
                             subtract( rem, prod, remL, base );
@@ -1859,7 +1859,7 @@
             }
 
             if (a) {
-                xc.unshift(a);
+                xc = [a].concat(xc);
                 ++ye;
             }