99 21 12 57 Chris Clements Rounding To the nearest 10.
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Transcript of 99 21 12 57 Chris Clements Rounding To the nearest 10.
99 21
1257 Chris Clements
Rounding
To the nearest 10
<date>
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!
continued
1) Identify the units digit.
Onto the next step. Can you remember it?
continued
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?
continued
3) If the units digit is a 5, 6, 7, 8, or 9 we round up.
continued
Lets have a go at these;
continued
Activity
<type here>
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!