Explain how you use a quick picture to find the quotient and remainder

Well you need to make an example question.
So lets say...There are 40 students in math class. The teacher needs to split the group up into equal sets of 5. How many groups can be made? How many students are left over? 
From there you can tell that you need to make groups of 5 to get your quotient which in our case is 8 leaving us with no remainder. However if you were to make that 41 students then you would have a remainder of 1 because whatever is not in your group is your remainder.

Idon’t understand this but 90