Chris Clements

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1257 Chris Clements

Rounding

Up or down?

<date>

Learning Objective:

<Steps to success>

Rounding

Rounding is used to approximate or estimate.

Rounding is used to approximate or estimate.

Rounding is used to approximate or estimate.

Numbers are usually rounded up or down to the nearest 10, 100,

1000, 10 000, 100 000 or even a 1, 000 000!

Numbers can be rounded either up or down

Lets see how well you are doing.

Step 1 in the steps to success

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1) Identify the units digit.

Take a look at these number lines.

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If a number ends in a 5, 6, 7, 8 or 9

If a number ends in a 1, 2, 3 and 4

So 15, 16, 17, 18 and 19 round up

So 21, 22, 23 and 24 round down

Now for the next 2 steps to success.

Do you think you know them?

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2) Numbers that end with a 5, 6, 7, 8 or 9 round up

3) Numbers that end with a 1, 2, 3 or 4 round down

Can you see if these numbers need to be rounded up or down.

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Is it closerto 20 or 30?

ROUND DOWN!Does it end in a

1, 2, 3 or 4?

Is it closerto 30 or 40? ROUND UP!

Does it end in a5, 6, 7, 8 or 9?

21 22 23 24 25 26 27 28 29

31 32 33 34 35 36 37 38 39

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51 52 53 54 55 56 57 58 59

71 72 73 74 75 76 77 78 79

61 62 63 64 65 66 67 68 69

91 92 93 94 95 96 97 98 99

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Round up Round down

Do these numbers;

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When rounding up or down 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.

Rounding up or downSteps to success

Activity<type here>

Plenary28 children go camping. They have

a huge tents which 10 children can sleep in. Will they need to round up or down to work out how many tents are needed?

How many tents will they need?

If 23 children went, why would it be a bad idea to round down?

Why is this more difficult to do?

Will 238 round up or down?

Plenary28 children go camping. They have

huge tents which 10 children can sleep in. Will they need to round up or down to work out how many tents are needed?

Round up!

How many tents will they need?

If 23 children went, why would it be a bad idea to round down?

Why is this more difficult to do?

How many tents will they need?

If 23 children went, why would it be a bad idea to round down?

Will 238 round up or down?

Why is this more difficult to do?

How many tents will they need?

If 23 children went, why would it be a bad idea to round down?

33 children will have

nowhere to sleep

Round up!