diff --git a/src/math/cmplx/sqrt.go b/src/math/cmplx/sqrt.go
index 0fbdcdedd3..741e5a8865 100644
--- a/src/math/cmplx/sqrt.go
+++ b/src/math/cmplx/sqrt.go
@@ -40,7 +40,7 @@ import "math"
 //                       1/2
 // Im w  =  [ (r - x)/2 ]   .
 //
-// Cancelation error in r-x or r+x is avoided by using the
+// Cancellation error in r-x or r+x is avoided by using the
 // identity  2 Re w Im w  =  y.
 //
 // Note that -w is also a square root of z. The root chosen