Just find the number that can divide by the whole. Say the question was
A pet shop have 20 pets. The same amount of pets are in each room. How many rroms could there be?
If there were 4 rooms, 5 pets would be in each. 20÷4=5. 4 goes into 20 so 4 could be an answer.
If there were 3 rooms, 6 rooms would have 3 pets and 2 would be left over. So it wouldn't work. You just need to find the number that goes into the whole with no remainder.
