search for: trasposing

I am just beginning to learn R. Please help. I have two matrices. One 20 columns by 16 rows represent student responses on a 20 question test. The second is 20 by 16 representing the correct responses 16 times. Subtracting one from the other should yield 0's if a response is correct. Yet Response minus Bigkey doesn't work. Documents indicate vectors should add and subtract, and