Golden Thumb
1-on-1 tutor for math & coding
Oliver is a 散打 (Chinese kickboxing) champion — sharp, fast, full of energy. But today, his battlefield is not the ring. It’s the quiet grid of a Killer Sudoku, Expert level.
He sits beside me, eyes bright, ready.
"Remember the 45 rule?" I ask.
He nods. "Of course." But I can tell — he thinks there's only one way to use it.
So I gently say, "There are more than one ways."
A few seconds pass. He stares at the grid, then his eyes light up.
"A column! I can use 45 here!"
He finds a column with all 9 cells filled with small cages and digits. Adds them up. One missing. He gets it. All on his own.
That was his first aha of the day.
But then, a small detour.
"Each row of 3 cells should add up to 15, right? 45 divided by 3?"
I smile. "Not quite. Only all 9 cells together add to 45. The 3-cell rows can vary."
He realizes instantly. No ego, no protest. Just curiosity.
I show him a small L-shape, marked sum 6.
"Wait," he says. "I might have something in my mind..."
He opens a side text editor. Lists possible combos: 1-3-2, 3-1-2...
He narrows down the possibilities. Tests them in place.
Then comes a larger cage: sum = 24.
He looks at a nearby cell that has a small value, maybe a 2.
"If this 2 is part of the 24, the rest would need to be 22 — which needs something bigger than 9! Not possible."
His logic is clean. Elegant. Quick.
I grin. I might be more thrilled than he is. But slowly, he starts to feel it too.
He is hooked — not in the game alone, but in reasoning. In discovering truth step by step. In earning each number.
From kickboxing to number battles. Today, Oliver fought a silent match. And came out grinning.
Postscript to educators and parents:
This is what it looks like when we give kids "just enough help without stealing the joy of discovery."
Let them try. Let them falter. Be patient. Share a tool — a rule — when the time is right.
The joy that follows is real, deep, and theirs forever.
