Drills

Counting possibilities exactly by systematic listing.

Author note — to cover

Fluency — listing factor pairs systematically, marked by the number of pairs or the missing partner of a given factor; counting all factors is left to the prime-factorisation drill (4 questions).
Systematic listing — counting arrangements and choices by ordered listing, small enough to enumerate (4 questions).
Constraints — listings with a fixed first digit or no repeats allowed, where unsystematic listing double-counts or misses cases (4 questions).

The test

—coming soon—

Where to go next

This mixed review uses the methods from these learning pages: