If it takes 4 balls of wool to make 8 caps, we would need to determine how many balls of wool it takes to make 6 caps. We need to divide 4 by 8. (4/8=1/2 or 0.5) Now, we need to multiply 0.5 by 6. (6x0.5=3) Malcolm needs 3 balls of wool to make 6 knitted caps.