diff --git a/AndroidCalculator/Calculator.swift b/AndroidCalculator/Calculator.swift
index cca7635..5ead6d0 100644
--- a/AndroidCalculator/Calculator.swift
+++ b/AndroidCalculator/Calculator.swift
@@ -33,31 +33,26 @@ class Calculator {
       }
       
       while true {
-        let indexOfMultiplication = calculatingFormula.firstIndex(of: "×")
-        let indexOfDivision = calculatingFormula.firstIndex(of: "÷")
+        let indexOf乘號 = calculatingFormula.firstIndex(of: "×")
+        let indexOf除號 = calculatingFormula.firstIndex(of: "÷")
         
-        if indexOfMultiplication == nil && indexOfDivision == nil {
+        if indexOf乘號 == nil && indexOf除號 == nil {
           break
         }
-        if indexOfMultiplication != nil {
-          if indexOfDivision == nil || indexOfMultiplication! < indexOfDivision! {
-            let number1 = Double(calculatingFormula[indexOfMultiplication! - 1])!
-            let number2 = Double(calculatingFormula[indexOfMultiplication! + 1])!
-            calculatingFormula[indexOfMultiplication! - 1] = String(number1 * number2)
-            calculatingFormula.remove(at: indexOfMultiplication! + 1)
-            calculatingFormula.remove(at: indexOfMultiplication!)
-            continue
-          }
+        if indexOf乘號 != nil && (indexOf除號 == nil || indexOf乘號! < indexOf除號!) {
+          let number1 = Double(calculatingFormula[indexOf乘號! - 1])!
+          let number2 = Double(calculatingFormula[indexOf乘號! + 1])!
+          calculatingFormula[indexOf乘號! - 1] = String(number1 * number2)
+          calculatingFormula.remove(at: indexOf乘號! + 1)
+          calculatingFormula.remove(at: indexOf乘號!)
         }
-        if indexOfDivision != nil {
-          if indexOfMultiplication == nil || indexOfDivision! < indexOfMultiplication! {
-            let number1 = Double(calculatingFormula[indexOfDivision! - 1])!
-            let number2 = Double(calculatingFormula[indexOfDivision! + 1])!
-            calculatingFormula[indexOfDivision! - 1] = String(number1 / number2)
-            calculatingFormula.remove(at: indexOfDivision! + 1)
-            calculatingFormula.remove(at: indexOfDivision!)
-            continue
-          }
+        if indexOf除號 != nil && (indexOf乘號 == nil || indexOf除號! < indexOf乘號!) {
+          let number1 = Double(calculatingFormula[indexOf除號! - 1])!
+          let number2 = Double(calculatingFormula[indexOf除號! + 1])!
+          calculatingFormula[indexOf除號! - 1] = String(number1 / number2)
+          calculatingFormula.remove(at: indexOf除號! + 1)
+          calculatingFormula.remove(at: indexOf除號!)
+          
         }
       }