Here are my codes but it seems to only store one number at a time. Hope to upgrade it to 2 or more numbers. I'm not to sure if if it's alright to modify "else if" statement? Open to ideas, Thank you! else if sender.tag == 16 { if operation == 12{ //Divide label.text = String(previousNumber / numberOnScreen) } else if operation == 13{ //Multiply label.text = String(previousNumber * numberOnScreen) } else if operation == 14{ //Subtract label.text = String(previousNumber - numberOnScreen) } else if operation == 15{ //Add label.text = String(previousNumber + numberOnScreen) } } else if sender.tag == 11{ label.text = "" previousNumber = 0; numberOnScreen = 0; operation = 0;