diff --git a/token-erc-1155/chaincode-go/chaincode/contract.go b/token-erc-1155/chaincode-go/chaincode/contract.go
index def4e71b..0a431dbd 100644
--- a/token-erc-1155/chaincode-go/chaincode/contract.go
+++ b/token-erc-1155/chaincode-go/chaincode/contract.go
@@ -1151,9 +1151,9 @@ func sub(b uint64, q uint64) (uint64, error) {
 
 	// Check overflow
 	var diff uint64
-	diff = q - b
+	diff = b - q
 
-	if diff > q {
+	if diff > b {
 		return 0, fmt.Errorf("Math: subtraction overflow occurred  %d - %d", b, q)
 	}