Rounding Whole Numbers

Rounding Whole Numbers

Welcome

Grade 7ASJ Math Class

Click the audio button

Objectives:

By the end of the lesson students will be able to:

• Round numbers to the nearest Ten

• Round numbers to the nearest Hundred

• Round numbers to the nearest Thousand

Instructions

Take your time to read each slide

Watch the videos and write down examples

Answer each question

Poll

Do you think 84 is closer to 80 or 90?

• It is closer to 90

• It is closer to 80

• It's in the middle

Open Ended

What comes to mind when you hear the word 'rounding'?

What is Rounding?

Rounding means making a number simpler but keeping its value close to what it was.

Sometimes we want to add numbers in our head but the numbers are a bit tricky so instead we can estimate (take a good guess) to the answer.

It is easier if we use numbers that are in multiples of 10s, 100s or 1000s and so forth.

Rounding RULES

• Look for the test digit and the rounding digit.

• The test digit is the digit that is to the right of the rounding digit.

• The rounding digit is the number that is being rounded.

• If the test digit is 5, 6, 7, 8 or 9, round up adding 1 to the rounding digit.

• If the test digit is 4, 3, 2, 1 or 0, round down.

Rounding to the nearest Ten means finding which multiple of ten they are nearest to.

Example: 63 is rounded to 60 because the test digit in the units place is less than 4 so we round down to the nearest multiple of ten.

Multiple Choice

Round 21 to the nearest Ten

• 30

• 20

• 25

• 21

Multiple Select

Rounding to the nearest Ten means

• Finding the number closest to the multiple of ten

• A number that ends with 1, 2, 3, or 4

• Any number that ends with zero

Rounding to the nearest Hundred means which multiple of hundred they are nearest to.

Example: 462 is rounded to 500 because the test digit in the tens place is larger than 5 so we round up.

Multiple Choice

Round 367 to the nearest Hundred

• 300

• 360

• 400

• 370

Rounding to the nearest Thousand mean which multiple of Thousand they are nearest to.

Example: 7412 is rounded to 7000 because the test digit in the hundreds place is 4 or less so we round down

Multiple Choice

Round 4578 to the nearest Thousand

• 4000

• 3000

• 4500

• 5000

Multiple Choice

When rounding numbers, if the test digit is 5, 6, 7, 8, or 9

• Add a zero to the end

• Round up

• Leave it alone

• Round down

Multiple Choice

Round 139 to the nearest Ten

• 135

• 100

• 130

• 140

Multiple Choice

Round 2787 to the nearest Hundred

• 2800

• 2700

• 2780

• 2750

Multiple Choice

Round 18370 to the nearest Thousand

• 18300

• 19000

• 18000

• 18500

Multiple Choice

When rounding numbers, if the test digit is 4 or less

• Round up

• Add zeros

• Round down

• Leave it alone

Summary

• Rounding means making a number simpler but keeping its value close to what it was.

• Rounding to the nearest Ten, Hundred and Thousand means finding the numbers closest to the multiples of 10, 100 and 1000.

• If the test digit is 5 or more, round up adding 1 to the rounding digit. If the test digit is 4 or less round down.