The question amounts to 90/4=45/2 because 2 is a common factor to both numbers. This is a way of asking: what's half of 45? The answer is 22 with a remainder of 1, or 22 1/2 or 22.5. This is the answer if we divide 4 into 90: we can only take 22 4's away from 90 (4*22=88), and there's a remainder of 2.