# Surf for More Math

## Lesson 5 - Estimating Sums and Differences

To encourage students to have fun on the Web while learning about Estimating
Sums and Differences, here are some games and interactive activities
they can do on their own or in pairs.

**Goal **

Estimate sums and differences of 2-digit numbers.

**Builds Upon **

Student Book pages 90-91

**Instructions for Use **

Estimate
the Sum of 2 Numbers lets students estimate the sum of 2 numbers.

To use Estimate the Sum of 2 Numbers , click
the 'Start Addition' button and read the equation in the text fields.
Have students click the button to indicate if students have the correct
answer.

Estimating
Differences lets students estimate the difference of 2 numbers.

To use Estimating Differences, click the 'Start
Subtraction' button and read the equation in the text fields. Have students
click the button to indicate if students have the correct answer.