根據題目，除以 0 就會變成 0

AndroidCalculator/Calculator.swift

@@ -74,6 +74,10 @@ class Calculator {
         tempFormula.append(number)
       }
       
+      if ["inf", "-inf", "nan"].firstIndex(of: tempFormula.last!) != nil {
+        tempFormula = ["0"]
+      }
+      
       return tempFormula.last!
     }
   }