Understanding Factors Through Divisibility

This is appropriate for 4th or 5th graders and involves finding the smallest number divisible by 2, 3, 4, 5, 6, 9, and 10.

Directions: Teach the students how to tell if a number is divisible by 2, 3, 4, 5, 6, 9, & 10.

Give groups ofu00a0two tou00a0four students the divisibility rules on a sheet of paper, and challenge them to find the smallest number divisible by all of the numbers listed above. Eventually the students, with or without help from the teacher, will come to realize that numbers divisible by 4 are also divisible by 2, so they don't have to think about the divisibility rule for 2. Similarly, numbers divisible by 9 are also divisible by 3, and numbers divisible by 10 are also divisible by 5. Numbers divisible by 6 are divisible by 2 and 3. So, the students must only focus on findingu00a0a number that is divisible by 4, 6, 9, and 10.