Math Focus 4
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## CHAPTER 3: ADDITION AND SUBTRACTION

### Lesson 6: Estimating Differences

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

Goal

Use your own strategies to estimate differences.

Builds Upon

Student Book page 83

Instructions for Use

Home Run Derby Math lets students practice estimating sums and differences.

Estimation Vally Golf lets students practice estimating sums and differences.

QUIA Math Journey lets students practice adding and subtracting 3- and 4-digit numbers.

To use QUIA Math Journey, read the directions, click “3-digit numbers” and “4-digit numbers” under
“Addition” or “Subtraction”, and click on “Begin the Game”. A problem will be displayed for you to solve. Your objective is to fly around the world, city by city, by solving problems like this. Although the problems must be answered exactly, estimate to check that each answer that you input into the empty answer box is reasonable before clicking on “Check Answer”. If an answer is right, you will score air distance travelled and receive a new problem. If it is wrong, you will miss your flight and be shown the correct answer. Click on “Continue” to get a new problem.  If you miss three flights, the game ends. To play a new game at any time, click on “Start over”.