diff --git a/src/main/java/fr/nancy/iut/CalcEngine.java b/src/main/java/fr/nancy/iut/CalcEngine.java
index 233050f21ad75909796bb866113bb7351fd9ee93..f5399638fa3420a7b39a2e0f6a7d66c93e736408 100755
--- a/src/main/java/fr/nancy/iut/CalcEngine.java
+++ b/src/main/java/fr/nancy/iut/CalcEngine.java
@@ -72,7 +72,7 @@ public class CalcEngine
         if (previousOperator == '+') {
             displayValue = leftOperand + displayValue;
         }
-        else {
+        else if (previousOperator == '-') {
             displayValue = leftOperand - displayValue;
         }
         leftOperand = 0;