Author note — to cover

Multiples and common multiples, and the divisibility tests for 2, 3, 4, 5, 9 and 10 applied to three- and four-digit numbers. LCM method lives on lcm-from-prime-factors; primality testing by trial division lives on primes-and-primality. Both tiers. (N4)

Introduction

—coming soon—

Practice and continue

Practice

Multiples and divisibility tests

The multiples of a number, and the tests for divisibility by 2, 3, 4, 5 and 9.

Next lesson

Primes and testing for primality

What makes a number prime, why 1 is not, and trial division up to the root.