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1257 Chris Clements

Rounding

To the nearest 10

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Learning Objective:

<Learning Objective>

Rounding

Rounding is used to approximate or estimate.

Numbers are usually rounded to the nearest 10, 100, 1000, 10 000, 100 000 or even a 1, 000

000.Decimals can also be rounded, usually to

the nearest tenth, hundredth, thousandth…

Rounding whole numbers

Negative numbers are also whole numbers e.g. -1, -2, - 3…

Whole numbers (also called integers) are counting

numbers e.g. 1, 2, 3, 4…

Decimals are not whole numbers e.g. 0.4, 7.4, 2.36, 7.32…

Fractions are not whole numbers e.g. ½ 2 ¾, 25 ¼ …

Decimals are not whole numbers e.g. 0.4, 7.4, 2.36, 7.32…

Rounding to the nearest 10

When rounding to the nearest 10 there are three main things to remember;

1) Identify the units digit. 2) If the units digit is a 1, 2, 3 or 4

we round down.3) If the units digit is a 5, 6, 7, 8, or

9 we round up.continued

When rounding to the nearest 10 there are three main things to remember;

1) Identify the units digit. 2) If the units digit is a 1, 2, 3 or 4

we round down.3) If the units digit is a 5, 6, 7, 8, or

9 we round up.

Steps to success

When rounding to the nearest 10 there are three main things to remember;

1) Identify the units digit. 2) If the units digit is a 1, 2, 3 or 4

we round down.3) If the units digit is a 5, 6, 7, 8, or

9 we round up.

Lets see how well you are doing.

REMEMBER Step 1!

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1) Identify the units digit.

Onto the next step. Can you remember it?

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2) If the units digit is a 1, 2, 3 or 4 we round down.

continued

Now for the final step. Can you remember it?

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3) If the units digit is a 5, 6, 7, 8, or 9 we round up.

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Lets have a go at these;

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Activity

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Plenary

At a builders yard bricks are sold in packs of ten. Jim wants 87 bricks to fix a broken wall. How many bricks must he buy?

If Jim went to buy 14 more bricks, what would happen if he rounded down to 10 and bought one more pack?Round 356 to nearest

10Round 2732 to nearest 10

What makesthese more

difficult?

90 bricks (9packs of 10)

He would be 4 bricks shortand will need to go

back again!

360

2730

He would be 4 bricks shortand will need to go

back again!