Post on 06-Jan-2018
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transcript
Rounding Numbersto the
Nearest Hundred
by Mrs. Zagrodny
When you find the hundred that is
closest to a number, you areroundin
g.
For example, 400 is the closest ten to 360.
So, 360 to the nearest 100 is rounded to 400.
Again, let’s think about a number line like a
roller coaster.
You might think about a number line that
looks like this:
100 300
200
On this number line, what number would come half
way between 100 and 200?
100 300
200
150
What number would come half way between 200 and
300?
100 300
200
150
250
What hundred would be next?
100
300
200
150 250 350
400
What number would be half way between?
Can you guess about where 170 would be on this number line?
100 300
200
150 250
350
40
170
100
300
200
150 250
350
400
170
If the roller coaster stopped, what number
would it roll to?
Can you guess about where 230 would be on this number line?
100
300
200
150 250 350
400
230
100
300
200
150
250
350
400
230
If the roller coaster stopped, what number
would it roll to?
Can you guess about where 360 would be on this number line?
100
300200
150
250
350
400
360
What would you round it to?
100 300200
150 250
350
400
360
Can you guess about where 410 would be on this number line?
100 300200
150
250 350
400410
What would you round it to?
100
300200
150
250 350
400410
Can you guess about where 190 would be on this number line?
100 300
200
150 250 350
400190
Can you guess about where 190 would be on this number line?
100
300
200
150
250
350
400190
100
300
200
150
250
350
400190
What would you round it to?
What about a number like 250? It’s right in the
middle!
100
300
200
150
250
350
40
Our rule is to round to the next hundred.
100
300200
150 250 350
400
100 300200
150
250 350
40
Tell a number that would round to 100.
110120
130140
When you round to the nearest hundred, look in the tens place.
If it has 1,2,3, or 4 round down.If it has 5, 6 ,7, 8, or 9 round up.
To round remember this rhyme,
5, 6, 7, 8, 9
GO UP all the time!!
Rounding numbers is so fun,We will do it 'till we're done.
If a number's 1-4,Round it down right through the
floor.If a number's 5-9,
Round it up it is just fine. Round up,
Round down, 1,2,3,4 --- 1-2, 3-4
Now it’s your turn!
You can get some help from the number line.
What hundred is closest to
560?
Put your bean on the closest hundred.
What hundred is closest to
790?
Put your bean on the closest hundred.
What hundred is closest to
830?
Put your bean on the closest hundred.
What hundred is closest to
990?
Put your bean on the closest hundred.
What hundred is closest to
650?
Put your bean on the closest hundred.
What hundred is closest to
940?
Put your bean on the closest hundred.
Are you roller
coaster ready for an assignment
?