diff --git a/src/gadgets/interpolation.rs b/src/gadgets/interpolation.rs
index 3bcecdae..799349ef 100644
--- a/src/gadgets/interpolation.rs
+++ b/src/gadgets/interpolation.rs
@@ -17,13 +17,9 @@ impl<F: Extendable<D>, const D: usize> CircuitBuilder<F, D> {
         // x  -> a1 + (x-a0)*(b1-a1)/(b0-a0)
 
         let one = self.one_extension();
-        let (x_m_a0, b1_m_a1) = self.double_arithmetic_extension(
-            F::ONE,
-            F::NEG_ONE,
-            one,
+        let (x_m_a0, b1_m_a1) = self.sub_two_extension(
             evaluation_point,
             interpolation_points[0].0,
-            one,
             interpolation_points[1].1,
             interpolation_points[0].1,
         );