Type in a number with your number keys. Click the calculator function you want to use. Type a new number and press the equal button to get the result. To start over just type in a new number (or press start).
The problem you all seem to have is that you can only make 1-digit numbers. You have to take whatever number is being pressed and multiply it by 10 as soon as the next number is being pressed. Fx if I press 7 and then 5, my number will become 7 · 10 + 5 = 75. So you constantly have to multiply the new number you get by 10. Hope that helped some of you out ;) Have fun :)
