diff --git a/src/script_number.js b/src/script_number.js
index 5177a8c..2c1a0ce 100644
--- a/src/script_number.js
+++ b/src/script_number.js
@@ -11,8 +11,6 @@ function decode (buffer, maxLength, minimal) {
     }
   }
 
-  var result
-
   // 40-bit
   if (length === 5) {
     var a = buffer.readUInt32LE(0)
@@ -22,6 +20,8 @@ function decode (buffer, maxLength, minimal) {
     return b * 0x100000000 + a
   }
 
+  var result = 0
+
   // 32-bit / 24-bit / 16-bit / 8-bit
   for (var i = 0; i < length; ++i) {
     result |= buffer[i] << (8 * i)