Update CalculatorResource.java

src/main/java/resources/CalculatorResource.java

@@ -79,7 +79,7 @@ public class CalculatorResource {
             numbers[i] = Integer.parseInt(split[i]);
         }
 
-        int sum = split[0];
+        int sum = numbers[0];
         for(int i = 1; i < numbers.length; i++){
             sum -= numbers[i];
         }