1. WJEC Past Paper Questions (with Answers).
Estimation
WJEC Past Paper Questions
(with Answers).

3. 8·6 = 8610 so 8·6  73 = 8610 73= (8673) 10 =6278 10 =627·8
860 = 86  10 and 7·3 = 73 10 so
860  7·3 = 86  10  73  10 = 86  73  10  10
= (86  73) = 6278
6278  73 = 86

4. Using Estimation
8 x 70 = 560 so the answer must be about 560 so
8·6 x 73 = 627·8
900 x 7 = 6300 so the answer must be around 6300, so
860 x 7·3 = 6278
6278  73 = 86

6. 4·5 = 45  10 and 6·7 = 67  10 so
4·5 x 6·7 = 45  10 x 67  10 = 45 x 67  10  10
= (45 x 67)  100 = 3015  100 = 30·15
450 = 45 x 10 and 0·67 = 67  100 so
4·5 x 6·7 = 45 x 10 x 67  100 = 45 x 67 x 10  100
= (45 x 67)  10 = 3015  10 = 301·5
30·15 = 3015  100 and 3015  45 = 67 (from question)
30·15  45 = 3015  100  45 = (3015  45)  100
=67  100 = 0.67

7. Using Estimation
5 x 7 = 35 so the answer must be about 35
So 4·5 x 6·7 = 30·15
500 x 0.6 = 300 so the answer must be about 300
4·5 x 6·7 = 301·5
30  45 is a little smaller than 1 and 3015  45 = 67 (from question)
So 30·15  45 = 0.67

9. 2·8 = 28  10 and 4·9 = 49  10 so
2·8 x 4·9 = 28  10 x 49  10 = 28 x 49  10  10
= (28 x 49)  100 = 1372  100 = 13·72
14 = 28  2 and 490 = 49 x 10 so
14 x 490 = 28  2 x 49 x 10 = 28 x 49  2 x 10
= (28 x 49) x 5 = 1372 x 5 = 6860
137·2 = 1372  10 and 1372  49 = 28 (from question)
137·2  49 = 1372  10  49 = (1372  49)  10
=28  10 = 2.8

10. Using Estimation
3 x 5 = 15 so the answer must be about 15
2·8 x 4·9 = 13·72
10 x 500 = 5000 so the answer must be about 5000
14 = 28  2 so you need to half the answer.
1372  2 = 686 so the answer must be 6860
1372  49 = 28 (from question)
100  50 = 2 so the answer must be about 2
137·2  49 = 2.8