## CHAPTER 1: NUMBER RELATIONSHIPS

**Lesson 1: Divisibility by 10, 5 and 2 **

Use these interactive activities to encourage students to have fun on the Web while learning about number relationships. Students can try these activities on their own or in pairs.

**Goal**

Create and use divisibility rules to determine if 10, 5, or 2 is a factor of a whole number.

**Builds Upon**

Student Book pages 4–6

**Instructions for Use**

**Divisible by 5** allows students to practice their knowledge of the divisibility by 5 rule.

To use Divisible by 5, read the rule, scroll down to “Practice”, and click on the “Start” button. A number will be displayed in the box below the “Start” button and a timer will begin counting elapsed time in the “Report Totals” box. Click on either the “Yes” or “No” box depending on whether you think the number is divisible by 5 or not. If your answer is correct a new number will be displayed. If not, an error box will pop up with the correct answer. In this case, click on the “X” to continue the game for as long as you like. You can also vary the game by scrolling down to “Play” and clicking on one of the choices shown in the 3 yellow boxes at left.