# Activities

• • • ##### Subject Area

• Math: Middle Grades Math: Number Sense

• ##### Author 6-8

45 Minutes

• ##### Device
• TI-73 Explorer™
• TI-Navigator™
• ##### Software

LearningCheck™ Creator

• ##### Report an Issue

A Prime Investigation with 7, 11, and 13 #### Activity Overview

In this activity, students will investigate the divisibility of 7, 11, and 13 and discover the divisibility characteristics of certain six-digit numbers. They will use the Integer Division feature of the TI-73 Explorer™.

#### Key Steps

• Students begin by using the Integer Division feature to explore the divisibility of a 3-digit number that is repeated to form a six-digit number by 7, 11, and 13. The Integer Division feature displays the quotient and the remainder. If there is no remainder, the calculator will display a zero.

• With the distributive property, students will discover why a 3-digit number repeated is always divisible by the product of 7, 11, and 13.

• Then students explore various divisibility rules, such as when numbers are divisible by 2, 3, 5, 7, and 11. Finally students develop their own divisibility rule.