diff --git a/calculator/calculator.app.js b/calculator/calculator.app.js
index 67a1e7b..07b6011 100644
--- a/calculator/calculator.app.js
+++ b/calculator/calculator.app.js
@@ -658,6 +658,10 @@ function buttonPress(val) {
         isDecimal = false;
       } else {
         currNumber = currNumber == null || hasPressedEquals === 1 ? val : (is0Negative ? '-' + val : currNumber + val);
+        // remove preceding 0 on integers
+        if (typeof currNumber === 'string' && currNumber.length > 1 && currNumber[0] === '0' && currNumber.indexOf('.') === -1) {
+          currNumber = currNumber.substr(1);
+        }
       }
       if (hasPressedEquals === 1) {
         hasPressedEquals = 2;