diff --git a/src/index.md b/src/index.md
index 9512d79..662412d 100644
--- a/src/index.md
+++ b/src/index.md
@@ -39,7 +39,7 @@ function calcPDiff(pScore, sF, sU)
   {
     const fDiff = pScore.sF - sF;
     const uDiff = pScore.sU - sU;
-    return Math.sqrt(fDiff^2 + uDiff^2);
+    return Math.sqrt(Math.pow(fDiff,2) + Math.pow(uDiff,2));
   }else{
     return undefined;
   }