Education Technology

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

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    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.

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

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    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.