/* other button clicks */
private void equals_Click(object sender, EventArgs e)
{
processInputtedNumber();
Math mathObj = new Math();
mathObj.Num1 = num1;
mathObj.Num2 = num2;
mathObj.Operation = operation;
answer = mathObj.calculate();
output.Text = answer.ToString();
numberString = "";
num1 = 0;
num2 = 0;
isSecondNumber = false;
negative = false;
decimalUsed = false;
}