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, 100, and 1000 are given. The rest of the lesson plan concentrates on the divisibility rules by 3, 9, 6, 4, and 8, and has plenty of exercises, including fun labyrinths and mystery number puzzles.