This clip explains how addition can be used to verify that the answer to a subtraction problem is correct.
Subject: check
The services of modern banks and savings institutions with an introduction to checking accounts, check registers, credit card transactions and bank
Subject: check
Transcript: EVERY MONTH. MAYBE THEY WERE AFRAID THAT WOULD SCARE ME INTO FORGETTING THE WHOLE THING. THEY DID ASK ME WHAT KIND OF FLOWERS I WANTED ON THE CHECKS, AND