# Surf for More Math

## CHAPTER 2: NUMBER TO 50

**Lesson 3: Representing Numbers to 50**

Use these interactive activities to encourage students to have fun on the Web while learning about the numbers to 50. Students can try these activities on their own or in pairs.

**Goal**

Representing numbers using place-value models and pictures.

[C, CN, V]

**Instructions for Use**

**Base Ten Blocks** lets students represent numbers using a model.

To use Base Ten Blocks, click on the blue icons at the top of each column to enter units or blocks. The number of blocks added to the work area automatically updates at the left of the workspace. If base ten blocks are moved into the wrong column, or if there are too many blocks in a column to represent a number, then the number update at the left remains blank. It reappears when changes are made that define a number.

Exchange pieces by dragging a base ten block one column to the right; it breaks apart to show that an exchange was made. To group pieces to make an exchange in 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.

Click on the "Show Problem" button to start an exercise in the specified base.