This is a complete lesson plan about the concept of divisibility and common divisibility rules. It briefly reviews the concepts of factor, divisor, and a number being divisible by another. Then, the "easy" divisibility rules by 2, 5, 10,...

This lesson focuses on prime numbers, numbers that can only be divided by one and itself. It explains the Fundamental Theorem of Arithmetic and the Sieve of Eratosthenes. Includes practice activities.