So Ethan, I hope I was able to help you with your homework today. Subtracting is easy.
It’s really just adding in reverse. It’s ok to use your fingers if you need to as a shortcut. See? It’s easy. I do that too. I still use my fingers sometimes and I’m a grown up. Nothing wrong with that if it helps. Now run along now.
(2 days later, Ethan has improved and is seen in his room working on math problems in his head.)
Ethan, you’re no longer using your fingers? You are subtracting and even adding numbers in your head?
You are so smart! I’m so proud of you, son.
How did you do that?
It’s called thinking. You should try it some time.