1. Can you solve this Anagram?
D O N G U N I R

2. To be able to round a number to the nearest 10,100,1000
L.O.
To be able to round a number to the nearest 10,100,1000
By the end of the lesson we will be able to:
explain the terms rounding and estimating
identify when to round up or down
round any number to the nearest 10,100,1000

3. Rounding is used to approximate or estimate.
Numbers can be rounded either
up or down
Numbers are usually rounded up or down to the nearest 10, 100, 1,000, 10,000, 100,000
or even a 1,000,000!

4. Rounding
Up or down?

5. round up round down So 15, 16, 17, 18 and 19 round up to 20
Take a look at these number lines. 10 11 12 13 20 14 15 16 17 18 19
If a number ends in a
5, 6, 7, 8 or 9
round up
So 15, 16, 17, 18 and 19 round up to 20 21 22 24 20 23 25 26 27 28 29 30
If a number ends in a
1, 2, 3 and 4
round down
So 21, 22, 23 and 24 round down to 20
continued

6. Rounding to the nearest 10
Steps to success
When rounding to the nearest 10 there are three main things to remember;
Identify the units digit.
If the units digit is a 1, 2, 3 or 4 we round down.
If the units digit is a 5, 6, 7, 8, or 9 we round up.
continued

7. Identify the units digit.
Step 1 in the steps to success
Identify the units digit. 1 2 2 5 7 7 3 9 9 7 4 4 9 5 5 2 3 3
continued

8. Can you see if these numbers need to be rounded up or down?21 22 23 24 25 26 27 28 29 2 3 3 20 30
Is it closer
to 20 or 30?
Does it end in a
1, 2, 3 or 4?
ROUND DOWN! 31 32 33 34 35 36 37 38 39 3 5 5 30 40
Does it end in a
5, 6, 7, 8 or 9?
Is it closer
to 30 or 40?
ROUND UP!
continued

9. 2 7 7 3 7 1 1 7 8 5 5 9 round up round down round up
Lets have a go at these; 20 27 30 2 7 7 3
round up 70 71 80 7 1 1
round down 7 80 85 90 8 5 5 9
round up
continued

10. 140
143
150 1 4 3 3 1 4
round down
330
334
340 3 3 4 4
round down 3 3
2140
2148
2150 1 4 8 8 2
round up 2 1 5 90 95
100 9 5 5 1
round up

11. Rounding
To the nearest 100

12. Rounding to the nearest 100
Steps to success
Identify the tens digit.
If the tens digit is a 1, 2, 3 or 4 we round down.
If the tens digit is a 5, 6, 7, 8, or 9 we round up.

13. There is a similar pattern for rounding numbers to the nearest 100
Identify the tens digit. 3 3 3 9 2 5 5 7 7 2 2 8 9 . 2 5 8 8 1
continued

14. 3 2 2 4 3 6 5 5 8 7 7 3 7 round down round up round down
Lets have ago at rounding to the nearest 100.
310
320
330
340
350
360
370
380
390
300
400 3 2 2 4
Is it closer
to 300
or 400? 3
round down
610
620
630
640
650
660
670
680
690
600
700 6 5 5 8
Is it closer
to 600
or 700? 7
round up
710
720
730
740
750
760
770
780
790
700
800 7 3
Is it closer
to 700
or 800? 7
round down
continued

15. 1 4 4 9 1 8 8 8 8 9 9 5 5 1 1 round down round up round up And more…
110
120
130
140
150
160
170
180
190
100
200 1 4 4 9
Is it closer
to 100
or 200? 1
round down
810
820
830
840
850
860
870
880
890
800
900 8 8 8 8
Is it closer
to 800
or 900? 9
round up
910
920
930
940
950
960
970
980
990
900
1000 9 5 5 1
Is it closer
to 900
or 1000? 1
round up

16. Now without the number line!4 7 7 9 5 2 2 1 1 7 9 8 6 6 1
continued

17. Can you write down the steps?
There is a similar pattern for rounding numbers to the nearest 1000
Can you write down the steps?
3690 to the nearest 1000 is 4000
continued

18. Round 6,750 to the nearest 1000 6,750 lies between 6,000 and 7,000.
6,100
6,200
6,300
6,400
6,500
6,600
6,700
6,800
6,900
7,000
6,750
6,750 lies between 6,000 and 7,000.
6,750 is closer to 7,000 than to 6,000.
Therefore,when 6,750 is rounded to the nearest 1000,it becomes 7,000.

19. Round 9,492 to the nearest 1000
9,000
9,100
9,200
9,300
9,400
9,500
9,600
9,700
9,800
9,900
10,000
9,492
9,492 lies between 9,000 and 10,000.
9,492 is closer to 9,000 than to 10,000.
Therefore,when 9,492 is rounded to the nearest 1000, it becomes 9,000.

20. Rounding to the nearest 10,100,1000
Remember to ask yourself:
Which two numbers can it round to?
These two numbers will change according to the nearest what you are rounding to
4,536
Nearest 10  4530 and 4540
Nearest 100  4500 and 4600
Nearest 1000  4,000 and 5,000

21. Rounding to nearest 10,100,1000 worksheet
Homework
Rounding to nearest 10,100,1000 worksheet

22. 20 40
640 20 40
190 80
100
550 60
520
250 70
120
370

23. 200
300
8,400
300
500
1,900
700
9,700
5,800
800
5,200
8,600
1000
1,100
3,800

24. 4,000
9,000
2,000
26,000
10,000
5,000
52,000
30,000