# Surf for More Math

## Lesson 3 - Mental Addition and Subtraction

To encourage your child to have fun on the Web while learning about
Mental Addition and Subtraction, here are some games and interactive
activities they can do on their own or in pairs.

**Goal **

Use mental math strategies to add and subtract
1-digit and 2-digit numbers.

**Builds Upon **

Student Book pages 84-85

**Instructions for Use **

Mentally
Adding 2-digit Numbers lets your child practice adding mentally.

To use Mentally Adding 2-digit Numbers, click
the 'Start Addition' button and read the numbers in the text fields.
Have your child input the answer in the text field and click the 'Check'
button to indicate if your child has the correct answer.

Mentally
Subtracting 2-digit Numbers lets your child practice subtracting
mentally.

To use Mentally Subtracting 2-digit Numbers,
click the 'Start Subtraction' button and read the numbers in the text
fields. Have your child input the answer in the text field and click
the 'Check' button to indicate if your child has the correct answer.