# Surf for More Math

## CHAPTER 3: ADDING AND SUBTRACTING DECIMALS

**Lesson 2: Communicating about Estimating and Calculating **

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**

Explain clearly how to estimate and calculate.

**Builds Upon**

Student Book pages 86–87

**Instructions for Use**

**Decimal Darts** is a one- or two-player game in which students use rounding, estimating, and calculating to win.

You will be shown a dart board with three balloons. The top of the dartboard is represented by one number and the bottom is represented by another number. You must type a number that you think will hit a balloon and then throw a dart. You may want to visualize a number line running along the length of the dartboard to help you. After each game, explain to your partner why you chose the numbers you did.