Question

a scientific calculator has 40 buttons, of which are white, 1/5 are grey, and 4 are orange. the rest of buttons are black. how many black buttons does the calculator have?​

Answer 1

40 divided by 5 is 8. So there is 8 grey buttons

8+4 is 12.

40-13=27

So there is 27 black buttons

Unless some are white but you never said the amount