Round to 1 s.f. and estimate
25 + 64
30 + 60
= 90
57 - 42
60 - 40
= 20
85 x 32
90 x 30
= 2700
78 ÷ 44
80 ÷ 40
= 2
24 x 31 + 67
20 x 30 + 70 = 600 + 70
= 670
145 + 75
100 + 80
=180
657 - 442
700 - 400
= 300
95 x 32
100 x 30
= 3000
655 ÷ 12
700 ÷ 10
= 70
35 x 42 + 78
40 x 40 + 80 = 160 + 80
= 240
215 + 347
200 + 300
= 500
4572 - 3299
5000 - 3000
= 2000
325 x 428
300 x 400
= 120000
9455 ÷347
9000 ÷300
= 30
6.66 x 5.55 + 7.77
7 x 6 + 8 = 42 + 8
= 50
8.02 + 7.45
8 + 7
= 15
7.94 - 4.77
8 - 5
= 3
49.92 x 99.10
50 x 100
= 5000
86.03 ÷ 3.25
90 ÷3
= 30
97.14 ÷ 4.36 - 10.23
100 ÷ 4 - 10 = 25 - 10
= 5
35.57 + 18.47
40 + 20
= 60
56.83 - 43.88
60 - 40
= 20
984.3 x 849.3
1000 x 800
=800000
3547.6 ÷ 98.42
4000 ÷100
= 40
408.25 ÷ 5.47 - 11.34
400 ÷ 5 - 10 = 80 - 10
= 70