# Surf for More Math

## Lesson 6 - Adding 2-Digit Numbers

To encourage students to have fun on the Web while learning about Adding
2-Digit Numbers, here are some games and interactive activities they
can do on their own or in pairs.

**Goal **

Add 2-digit numbers with and without regrouping.

**Builds Upon **

Student Book pages 92-93

**Instructions for Use **

Adding
2-Digit Numbers provides students with strategies to mentally add
2-digit numbers.

To find the sum of the two numbers, click the 'Start Addition' button.
Input the answer in the text box next to the 'Check' button, then click
'Check'. See if the answer is correct. Continue to find the sum of the
next two numbers.

The
Addition Machine lets students practice adding 1-digit and 2-digit
numbers.

To use The Addition Machine, choose a skill
level, type the answer in the text field, and click the red button to
check it.

Base
Block Addition lets students practice addition with and without
regrouping.

To use** **Base Block Addition,
drag a base block into a column to the left. If students move a block
one column to the right, it breaks apart to show the exchange, for example,
a 10-long for ten units. To group pieces to exchange the other direction,
click and hold the mouse key down while dragging a rectangle to "lasso"
the pieces. The newly grouped object can then be dragged into the next
column.

To complete a preset addition problem, select base 10 and click on
the 'Next Problem' button. Group any pieces and drag them into the next
column. Start with the 1s column and work to the 1000s column. The addition
solution will appear on the left.

To add the blocks together to create your own problem, click on the
'Create Problem' button and then use the blue buttons at the top to
enter blocks above and below the dashed line. As long as there are two
numbers correctly represented in the specified base, the addition problem
will appear on the left. To solve it, click on the 'Begin Problem' button
and then on any of the blocks in the workspace.