Subtraction Isn't 10−7. Subtraction Is Knocking Down Your Tower.
Kids aren't incapable of grasping the abstract — the abstract just has to become something they can touch, play with, and win at first. This is momomori's second principle: concrete before abstract.
When my son was five, doing subtraction worksheets made him cry.
Not because it was hard — because it was boring, because "10−7" was nothing to him. Three symbols. No weight, no warmth, no winning or losing.
Then we played a game: he built a tower out of blocks, and so did I. We played rock-paper-scissors, and the winner got to "knock down three of the other person's blocks."
That night he worked through a whole page of subtraction by himself. Nobody made him. He didn't even realize it was subtraction.
The abstract has to become an experience first
Numbers, time, money, probability — these are symbols humans invented to compress the world. To an adult they're tools; to a child they're noise.
Children understand the world in the opposite order:
- First comes the thrill of "I knocked down three of your blocks,"
- and only then the symbol "10 minus 3 equals 7."
Concrete first, abstract second. Get the order wrong, and learning becomes torture.
That's why I make games, not worksheets
Wrap subtraction inside a "rock-paper-scissors → knock down the tower" loop, and three things happen:
- Subtraction becomes a visible, satisfying action.
- The three-way choice on your turn (attack / build / defend) creates just enough strategic tension.
- Short rounds and comebacks lower the barrier to "one more round."
That loop later grew into my first game: NumWar. It's still in validation — I'm watching whether real children will spontaneously say those words:
One more round.
If they do, it means ability really can be played into being.