diff --git a/src/blocks.js b/src/blocks.js
index ba698531e..45b18631b 100644
--- a/src/blocks.js
+++ b/src/blocks.js
@@ -12349,7 +12349,10 @@ InputSlotMorph.prototype.evaluate = function () {
         return this.constant;
     }
     val = this.contents().text;
-    if (this.isNumeric && (!this.evaluateAsString || val === '')) {
+    if (this.isNumeric &&
+        !this.isAlphanumeric &&
+        (!this.evaluateAsString || val === '')
+    ) {
         return +val;
     }
     return val;