# Surf for More Math

## CHAPTER 8: ADDITION AND SUBTRACTION

**Lesson 3: Adding Two-Digit Numbers in Different Ways **

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 to add two-digit numbers with manipulatives.

[C, ME, PS, R, V]

**Instructions for Use**

**Addition Machine** lets students practice adding 2 one-digit numbers, adding 1 two-digit number and 1 one-digit number, and adding 2 two-digit numbers.

To use Addition Machine, select Level 2 to practise adding 2 one-digit numbers, and 1 two-digit number and 1 one-digit number. Enter your answer in the white box and click “Check my answer.” Your score is shown to the right. Select the Level for each question.

**Base Blocks Addition** has students use base ten blocks to model grouping when adding two-digit numbers.

To use Base Blocks Addition, set the columns to 2. Group 10 ones together from the ones column and drag them into the tens column. The sum is show on the right and illustrated with the blocks. Click Next Problem to see the next problem.

**Adding Practice** provides students extra practice adding 2 two-digit numbers.

To use Adding Practice, click on Lesson 10.6. Select the correct sum from the three choices. Click Check Your Answer. If your answer is correct, it will show your score and another question. If you are incorrect, you will be asked to try again. When you have completed several questions, click End the Quiz. Your final score is shown.