rounding numbers to the closest ten by debbie wilks
TRANSCRIPT
Rounding Numbersto the
Closest Ten
by Debbie Wilks
When you find the ten that is closest to a number, you are
rounding.
For example, 40 is the closest ten to 36.
So, 36 is rounded to 40.
Let’s think about a number line like a
roller coaster.
You might think about a number line that
looks like this:
10 3020
On this number line, what number would come half way between 10 and 20?
10 3020
15
What number would come half way between 20 and
30?
10 3020
15
25
What ten would be next?
10 30
20
15 25 35
40
What number would be half way between?
Can you guess about where 17 would be
on this number line?
10
30
20
15 25 35
40
17
10
30
20
15 25 35
40
17
If the roller coaster stopped, what number
would it roll to?
Can you guess about where 23 would be
on this number line?
10
30
20
15 25 35
40
23
10
30
20
15 25 35
40
23
If the roller coaster stopped, what number
would it roll to?
Can you guess about where 36 would be
on this number line?
10
30
20
15 25 35
40
36
What would you round it to?
10
30
20
15 25 35
40
36
Can you guess about where 41 would be
on this number line?
10
30
20
15 25 35
40
41
What would you round it to?
10
30
20
15 25 35
40
41
Can you guess about where 19 would be
on this number line?
10
30
20
15 25 35
40
19
Can you guess about where 19 would be
on this number line?
10
30
20
15 25 35
40
19
10
30
20
15 25 35
40
19
What would you round it to?
What about a number like 25? It’s right in the middle!
10
30
20
15 25 35
40
Our rule is to round to the next ten.
10
30
20
15 25 35
40
10
30
20
15 25 35
40
Tell a number that would round to 10.
1112
1314
When you round to the closest ten, look in the ones 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 ten is closest to 56?
Put your bean on the closest ten.
What ten is closest to 79?
Put your bean on the closest ten.
What ten is closest to 83?
Put your bean on the closest ten.
What ten is closest to 99?
Put your bean on the closest ten.
What ten is closest to 65?
Put your bean on the closest ten.
What ten is closest to 94?
Put your bean on the closest ten.
Are you roller
coaster ready for an assignment
?