# Surf for More Math

## CHAPTER 8: ADDITION AND SUBTRACTION

**Lesson 1: Adding and Subtracting Tens **

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

**Goal**

Use personal strategies for adding and subtracting tens with manipulatives.

[CN, ME, PS, R]

**Instructions for Use**

**Adding Tens** provides student practice with adding tens using a strategy.

To use Adding Tens, scroll down to the Practice section and click Start. Enter the sum of the two tens shown and click Check. A total of the number of correct and incorrect responses is shown. Click Report Totals to get a summary.

Scroll down to the Play section and select Countdown, Give Me Time, or 20 Questions. Click Start to begin answering the questions as in the Practice.

**Subtracting Tens** provides student practice with subtracting tens using a strategy.

To use Subtracting Tens, scroll down to the Practice section and click Start. Enter the difference of the two tens shown and click Check. A total of the number of correct and incorrect responses is shown. Click Report Totals to get a summary.

Scroll down to the Play section and select Countdown, Give Me Time, or 20 Questions. Click Start to begin answering the questions as in the Practice.