Why a Sudoku-solving program looks smart: Recursion, backtracking, and the idea of 'trying from the most likely failure points'

I was thinking about a program to solve Sudoku.You fill a 9x9 grid with numbers from 1 to 9. The same number must not be ...

A story about how I realized this is how applied math skills are acquired

It started with the recurrence relation function on the Casio FX-GC100 graphing calculatorSince a recurrence relation is ...