Rounding Decimals

Summary
This lesson is designed to reinforce the children?s understanding of rounding by introducing the rounding of decimals.

Objectives
• to explain how to round decimals to the nearest 10th, 100th and 1000th.

• to demonstrate a practical application of rounding.

Suggested Grades
3rd Grade
4th Grade

Excerpt
Using decimals is a good way to get a really accurate measurement of anything, but too many decimal places makes a number unwieldy and difficult to work with.

An example of this is pi which is the ratio of the circumference of a circle to its diameter. It is what we call a mathematical constant because it is always the same number on any circle. But the number of decimal places in pi is unlimited. For example, here is pi taken to the 10th place:

? 3.1415926535

This would be a very difficult number to work with because it is so long. We need to round it.

Continued...