Answer:
The blank space on the bottom of 5 would be 4 because 9 - 5 = 4.
8 would go to the top right section since 5 goes 8 times in 40.
Multiply them again to get 40 (which would go on the very bottom of the original 40 so put 4.
Then subtract it from 40 (place the 4 before oyu even subtract on both the top and bottom of the bar), to get 0.