This document provides information about estimation and rounding numbers to calculate estimated sums. It defines estimation as finding a number close to the actual or correct answer. To estimate a sum, each number should be rounded up or down to the nearest hundred or thousand before adding. Several examples are provided of rounding numbers and choosing the rounded addends to calculate estimated sums. The document suggests situations where estimation is useful, such as calculating travel time, grocery costs, or materials needed for a construction project.

2. Roundoffeachnumbertoits
highestplacevalue.

3. EXAMPLE:

4. 500

5. 7000

6. 800

7. 9000

8. 100

9. 500

10. 5000

11. 4000

12. It was Antonio’s Birthday
party. There were189
males and 98 females
who attended his party.
About how many people
attended the party?

13. Estimation
is finding a number close
enough to the right answer or
actual answer

14.  Round off the numbers first to
the highest place value before
adding.
How to find the
estimated sum?

15. It was Antonio’s
Birthday party. There
were189 males and 98
females who attended
his party. About how
many people attended
the party?

16. Situations
when we do
estimation

17. The amount of money we
need for buying our groceries
The time it will take to reach a
place like school or your home
The food a group of people
can consume in a week

18. The time needed to spend
studying all subjects for the
periodic exams
Amount of money and
materials needed to construct
a house or a building
The amount of money for
buying your food in school

19. Estimate the sum by rounding each
addend to the nearest
hundred/nearest thousand.
456
205
+
456
Estimat
ed Sum
Actual
Sum
+
5
481
+
2
927
Estimat
ed Sum
Actual
Sum
+

20. Estimate the sum by rounding each
addend to the nearest
hundred/nearest thousand.
123
987
+
Estimat
ed Sum
Actual
Sum
+
7
727
+
1
085
Estimat
ed Sum
Actual
Sum
+

21. Estimate the
sum by
rounding each
addend to the
nearest hundred
or thousand.

22. M
368
478
+ +

23. A
815
102
+ +

24. T
3
489
2
127
+ +

25. H
5
739
1
106
+ +

26. Choose the
rounded
addends.

27. Choose the
rounded addends.
+
a
.
b
.
c
.
234 342
200 +
300
300 +
300
300 +
400

28. Choose the
rounded addends.
+
a
.
b
.
c
.
359 256
300 +
200
300 +
300
400 +
300

29. Choose the
rounded addends.
+
a
.
b
.
c
.
4
689
4
679
4000 +
4000
5000 +
4000
5000 +
5000

30. Find the estimated sum. Match
column A with Column B.

31. Column A Column B
342 + 323
7 522 + 8 423
a. 16 000
___1.
___2.
___3.
d
c
a
___4.
553 + 182
6 359 + 3 754
b. 10 000
c. 800
d. 600
b