To find out how many more brussel spouts Melvin needs, you will subtract the total amount needed and the amount he has.
To find how many he needs you multiply 9 x 5 = 45 brussel sprouts.
If he has a dozen (12), Melvin will still need 33 brussel sprouts (45 - 12).
The equation showing this is:
(5 x 9) - 12 = b, where b is the number of brussel sprouts needed.
