Rounding And Estimating Worksheet Page 12
ADVERTISEMENT
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
184.6
MEP Y8 Practice Book A
To make sure that you obtain the correct answer when
you use a calculator,
ESTIMATE the answer mentally,
CALCULATE the answer using your calculator
and then
CHECK that the calculator answer is sensible
by comparing it with your mental estimate.
Example 2
×
Halim uses his calculator to work out
8 623
.
4 71
.
.
He gets the answer 406.1433.
Use an estimate to check his answer.
Solution
= 9
×
(a)
Estimate
5
=
45
Halim's answer should have been 40.61433.
Example 3
Jai carries out the following calculations on his calculator, and writes his answers
correct to 3 decimal places:
×
=
A
3 62
.
8 94
.
32 363
.
÷
=
B
47 92
.
2 17 1 512
.
.
×
=
C
184
3 616
.
665 344
.
(
)
+
×
=
D
21 4
.
19 7
.
3 61 14 837
.
.
Use estimates to decide which answers could be correct and which are definitely
incorrect.
Solution
= 4
×
A
Estimate
9
=
36
suggesting that Jai's answer could be correct.
= 50
÷
B
Estimate
2
=
25
showing that Jai's answer must be incorrect.
74
ADVERTISEMENT
0 votes
Related Articles
Related forms
Related Categories
Parent category: Education