Divisibility Rules

Introduce your students to divisibility rules with a lesson that encourages deep thinking and meaningful math talk between peers.
Need extra help for EL students? Try the The Factor Tree Strategy pre-lesson.
View aligned standards
Need extra help for EL students? Try the The Factor Tree Strategy pre-lesson.

Learning Objectives

Students will be able to use divisibility rules to determine factors of whole numbers.

The adjustment to the whole group lesson is a modification to differentiate for children who are English learners.

Introduction

(5 minutes)
• Write a large number on the board (e.g., 219,438) and ask students, "Is this number divisible by 3?"
• Take a quick poll or ask for students to respond with thumbs up or down.
• Explain: "Today we are going to learn some special rules that will help us recognize divisibility. By the end of our lesson, you will know some shortcuts that will make it easy for you to determine if numbers, even huge numbers like this, are divisible by other numbers like 2, 3, 4...!"
• Leave the number written on the board to revisit at the end of the lesson.

Beginning

• Use a smaller number as the introductory number for students to consider such as 2,364.
• Provide a student-friendly definition of "divisibility" in students' home language (L1) and English (L2) and display it throughout the lesson.

Intermediate

• Have students discuss with a partner whether or not the introductory number is divisible by 3 to activate their prior knowledge.