3 Ways to Check a Subtraction Problem

Here are 3 ways we are teaching the kids to check their subtraction problems.  First, they start out checking it with estimation to see if their answer is reasonable.  Next, they can check their regrouping if it is a regrouping problem by adding their regrouping numbers back together to make sure it equals up to the minuend (the top number in a subtraction problem).  Finally they can check their accuracy by using the inverse operation of addition and subtraction.  They can add the difference to the subtrahend (the number on the bottom of the problem).  I remember this because of a sub-marine is on the bottom like a subtrahend. Sub means under.  See the ways kids can check this below.  Hmmmm…could be a great anchor chart!! 🙂

3 Ways to Check a Subtraction Problem