Math Focus 4
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## CHAPTER 3: ADDITION AND SUBTRACTION

### Lesson 10: Communicating about Number Concepts and Procedures

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

Goal

Explain your thinking when estimating a sum or difference.

Builds Upon

Student Book pages 94–95

Instructions for Use

Maximum Capacity allows your child to practise estimating sums up to 4-digits.

To use Maximum Capacity, look at the illustration and read the step-by-step instructions and then click on “Play Now!” at upper left. On the next screen, click on “Play” to start the game. Click and drag as many gorillas as you can into the elevator, up to but not exceeding the weight capacity of the elevator. Then click on the flashing elevator button on the right. If the gorillas’ combined weight does not exceed the elevator’s weight capacity they will be delivered to the ball. Then you can click “continue” and the elevator will return to ground level for you to refill. If the gorillas’ combined weight exceeds the elevator’s weight capacity, the elevator will not work and you will have to click on “clear X” at the bottom of the “Weight Board” to begin reloading gorillas. You have 3 minutes to bring as many gorillas to the ball as you can, after which your score will appear. Click on “BACK” and then on “PLAY” to start a new round or on “HELP” if you need more advice.

QUIA Math Journey lets your child 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”.