# Surf for More Math

**CHAPTER 3: ADDING AND SUBTRACTING DECIMALS **

**Lesson 4: Adding Decimals Using Mental Math **

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

**Goal**

Solve problems by using mental math to add decimals.

**Builds Upon**

Student Book pages 92–93

**Instructions for Use**

**Addition of Decimals** allows students to practise adding decimals using mental math.

Read the instructions and then scroll down to the “Practice” box. Click “Start”, add the decimals and then click on the button that shows your answer. The activity will tell you if you are correct. Click “Start” to get a new problem.

**Laser Beam** allows students to estimate sums and differences by rounding decimals.

Blast meteors as you answer addition and subtraction questions. Select the “Intermediate” level. Round the decimals and then estimate the sum or difference.

**Adding and Subtracting Whole Numbers and Decimals** allows students to solve various types of questions involving adding and subtracting whole numbers and decimals.

Play this game like jeopardy. Select a category and point value and then answer the question.

**Math at the Mall** allows students to add and subtract decimals to purchase items at the mall.

Use the arrow keys to move your character around the mall. To get the various places in mall, please move your character to the very end of the pathway. At every location you will have to use your adding and subtracting skills to complete several tasks, such as depositing money at the bank, or purchasing toys at the toy store.