Okay... so the title is a lie! This is pretend real life math. Usually when we do math it turns into something else. I let her lead the lesson into something she wants to do. Here she is pretending to be a grocery store clerk and selling food to me with pretend money. She is using her cash register to check that all of the prices are added together correctly to give me a total. I pay her and she checks my money to be sure that I've paid her the right amount.