 Place value- rounding decimal numbers to the nearest whole number

# Place value- rounding decimal numbers to the nearest whole number

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## General

Students are able to round decimal numbers to the nearest whole number.

## Relevance

Discuss with students that it is important to be able to do this to increase their calculation speed.

## Introduction

The interactive whiteboard has a number of different numbers. Ask students to drag the whole numbers to one bin and the decimal numbers to the other bin. Discuss with students which numbers are easier than the others.

## Development

Explain to students that rounding relies on the number after the decimal point, the number in the tenths place. When a number is 4 or less, the number in the ones place stays the same. When a number is 5 or greater, you add 1 more to the number in the ones place. Practice this with the students. Students use the decimal place value chart. Emphasize that the decimal number must be correctly placed in the chart and to carefully look at the number in the tenths place.

Check that students are able to round numbers by asking the following questions:
- What does rounding mean?
- Which number do you look at to determine if you round to a whole number?
- What do you do if the number in the tenths place is a 5?
- What do you do with the number in the ones place if the number in the tenths place is 5 or more?

## Guided practice

Students first practice rounding numbers with 1 decimal place in a multiple choice setting. Then they round decimal numbers with 2 decimal places in an open question.

## Closing

Check that students are able to round decimal numbers by playing a game. Show the students a decimal number and ask if it should be rounded up or rounded down. Up = stand up, and down = sit down. Have students explain their reasoning (4 or less is round down, 5 or greater is round up).

## Teaching tips

Students who have difficulty rounding should start with decimal numbers with 1 decimal place. When they are comfortable with that, move to 2 decimal places. Students who are ready for more challenge can be asked to round to the tenths place. 