Factor Fiona

Fiona learned to see the blocks from her uncle, who built furniture.

She'd watch him look at a finished chair — a solid, whole thing — and somehow see, underneath, every joint and peg and plank that made it. "I can't help it," he told her. "Once you've built a chair, you can never look at one as just a chair again. You see how it goes together. And anything you can see how it's built, you can fix, or copy, or change."

Young Fiona started doing that with numbers. She'd take a number and pull it apart into the smaller numbers multiplied together to make it. Thirty-six? That was six sixes — or four nines, or two eighteens, or three twelves. Each number stopped being a lump and became a little kit of parts.

And just like her uncle and his chairs, once she could see what a number was built from, she could do things with it. Hard multiplications came apart into easy steps. Numbers that didn't seem related turned out to share a building block. The whole number world stopped being a row of solid walls and became a workshop full of parts she could mix and match.

The building blocks were a superpower for multiplying, Fiona showed kids.

A girl named Sana was stuck on a problem that needed *24 × something*, and the something was awkward.

"Don't multiply by all of twenty-four at once," Fiona said. "Take it apart. Twenty-four is eight times three. So instead of one scary multiply, do two friendly ones — multiply by eight, then by three. Or break it however helps. Six times four. Two times twelve. You pick the blocks that make your problem easiest."

Sana tried it, multiplying by the easy block first, then the next. "That was so much less scary," she said. "I just did it in two little steps instead of one big one."

"That's the whole trick," Fiona said. "A hard number is just easy numbers wearing a disguise. Take it apart into its blocks, deal with the blocks one at a time, and the hard thing quietly falls to pieces in your hands."

Sana wrote: Break the number into factors. Do the easy pieces one at a time.

What Fiona loved most was the moment a kid stopped seeing a number as a wall.

"Walls are scary because you can't get through them," she told a boy named Theo, who used to freeze at big numbers. "But a number was never a wall. It was always built — and anything built can be taken apart." She tapped her tool belt. "Once you know what a number is made of, you're not stuck staring at the outside anymore. You're holding the pieces. And when you're holding the pieces, you're the one in charge. You can rebuild it any way you like."

Theo took a number that had scared him and pulled it apart into its factors, naming each block. "It's not a wall," he said slowly, turning the pieces over in his head. "It's a kit."

"It was always a kit," Fiona said. "You just couldn't see the seams yet."