Press the A Button to see if the inputted number is less than 100 Press the B button to see if the number is less than 0 (Good Input=Above 0, Bad Input= below 0) Press the C button to see if the number is between 0 and 100 (Between 0&100 = good input) Press the E button to enter the total purchase amount and the discount percentage without the percent sign and it will calculate the new total amount and how much the discount subtracted but if the original amount is less than 2000 then no discount is applied. Press the F button to add together 3 grades adn find the grade point average letter that corresponds to your grade point average Press the G button to input 3 numebr and figure out which one of the 3 numbers inputed is the highest and the lowest value