diff --git a/AndroidCalculator/Calculator.swift b/AndroidCalculator/Calculator.swift
index 38c5924..d3783fe 100644
--- a/AndroidCalculator/Calculator.swift
+++ b/AndroidCalculator/Calculator.swift
@@ -55,7 +55,17 @@ class Calculator {
           
         }
       }
-      
+      while calculatingFormula.count > 1 {
+        let number1 = Double(calculatingFormula[0])!
+        let number2 = Double(calculatingFormula[2])!
+        if calculatingFormula[1] == "+" {
+          calculatingFormula[0] = String(number1 + number2)
+        } else {
+          calculatingFormula[0] = String(number1 - number2)
+        }
+        calculatingFormula.remove(at: 2)
+        calculatingFormula.remove(at: 1)
+      }
       
       if Double(calculatingFormula.last!)!.truncatingRemainder(dividingBy: 1) == 0 {
         var number = calculatingFormula.popLast()!