Every day in the grown-up world, we face situations that call for adding, subtracting, multiplying, or dividing. We figure tips in restaurants, decide when to leave home to get to the movies on time, estimate the price of a sale item, keep track of what we’re spending while shopping in the supermarket, double and halve recipes, and on and on. At least half of the time, we do these calculations when we’re out and about, without pen and paper handy, which means we have to figure mentally. Because figuring in our heads is such an important life skill, it should have a regular role in your classroom teaching.