Math Lesson 3 Instruction, page 1

Instruction 3-1

ROUND OFF DECIMALS
CA GR4 NS 2.2, CA GR5 NS 1.2

Rounding off decimals is exactly like rounding off whole numbers. To round to the nearest tenth, you do the same thing as when you round to the nearest multiple of 10, except you are working with a different place value.

There are two methods you can use to round decimals.

Method A:

You can use a number line to round decimals.

Round 13.4 to the nearest whole number.

Think, is 13.4 closer to 13 than it is to 14? Check your answer.

Round 13.4 down to 13.

Method B:

You can also use place-value to round decimals.

To round to the nearest number use place-value. Look at the digit in the place to the right of where you want to round. Determine whether the digit is greater than 5 or less than 5. Round appropriately.

Example 1	Round 27.58 to the nearest tenth.	27.58
	Compare the digit to 5. If it is less than 5, round down. If it is more than 5, round up.	8 > 5, round up 27.6
Example 2	Round 12.534 to the nearest hundredth.	12.534
	Compare the digit to 5. If it is less than 5, round down. If it is more than 5, round up.	4 < 5, round down 12.53
Example 3	Round 93.76 to the nearest whole number.	93.76
	Compare the digit to 5. If it is less than 5, round down. If it is more than 5, round up.	7 > 5, round up 94

Worksheet 1 Round Decimals on a Number Line

Worksheet 2 Round Decimals to the Hundredth

Worksheet 3 Round Decimals to the Tenth

Worksheet 4 Round Decimals to the Hundredth

Worksheet 5 Round to the Underlined Place Value

Links for Students, Parents and Teachers

Now let's do Practice Exercise 3-1 (top).

Next Page: Compare and Order Positive and Negative Fractions, Decimals, Mixed Numbers (top)

Pre-Test		Post-Test
Q&A	Integer Grab Bag	Q&A