To solve this problem, we first need to find out how many of Justin's toys will fit on the shelves. If we have shelves, and toys fit on each shelf, we can multiply those two numbers together to find out the total number of toys that will fit. Let's let represent the number of toys that will fit.

Justin has toys, so to find out how many don't fit on the shelves we need to know what is left over, so we subtract. Let's let represent the number of toys left over.