Good morning from Canada!
What we know:
-quire=25 sheets
-ream=100 sheets
So, we are looking for how many quires can fit into a ream. All we have to do is divide the number of sheets in a ream (100) by the number of sheets in a quire (25) because dividing allows us to see how many times a specific number can go into another number, which is what we are looking for. (How many quires are in a ream).
100/25=4
Therefore 4 quires can fit into a ream.
Hope this helps!