# Revision starter 4

```GCSE Higher Revision Starters 4
Grade D – One number as a % of another
Write these as percentages
8 out of 10
3 out of 5
7 out of 25
17 out of 50
1 out of 20
124 out of 200
84 out of 400
In a class of 20 there are 8 boys. What
percentage of the class are girls?
A gardener plants 7 seeds and only 3 of
them grow. What percentage of the
seeds grew?
Grade D – One number as a % of another
Write these as percentages
8 out of 10
3 out of 5
7 out of 25
17 out of 50
1 out of 20
124 out of 200
84 out of 400
80%
60%
28%
34%
5%
62%
21%
In a class of 20 there are 8 boys. What
percentage of the class are girls?
40%
A gardener plants 7 seeds and only 3 of
them grow. What percentage of the
seeds grew?
42.9%
Grade B Number – Standard Form
Write these numbers into ordinary form
3 x 105
6.4 x 103
2.81 x 106
6 x 10-2
5.9 x 10-4
3.783 x 10-7
Write these numbers into standard form
560000
3040
391000000
0.007
0.0000064
0.21
3.4 x 102 + 4.18 x 104
2.11 x 105 - 9.6 x 103
4 x 10-2 + 6.3 x 10-1
5.7 x 105 - 2.6 x 10-3
Grade B Number – Standard Form
Write these numbers into ordinary form
3 x 105
300000
6.4 x 103
6400
2.81 x 106
2810000
6 x 10-2
0.06
5.9 x 10-4
0.00059
3.783 x 10-7 0.0000003783
Write these numbers into standard form
560000
5.6 x 105
3040
3.04 x 103
391000000
3.91 x 108
0.007
7 x 10-3
0.0000064
6.4 x 10-6
0.21
2.1 x 10-1
3.4
x 10
+ 44.18 x 104
4.214
x210
5 -5 9.6 x 103
2.11
2.014x x1010
-1 6.3 x 10-1
-2 +
x 10
43.4
x 10
5.7 xx 10
1055 - 2.6 x 10-3
5.7
Grade B – Calculating with Standard Form
Work these out without a calculator
(3 x 105)
x (2 x 103)
(6 x 103) x (7 x 107)
(3.2 x 102) x (5 x 108)
(2 x 10-2) x (4 x 107)
(2.1 x 10-5) x (2 x 10-2)
(8 x 10-5) x (4 x 10-4)
Work these out without a calculator
(8 x 109)
÷ (2 x 103)
(2.6 x 103) ÷ (1.3 x 108)
(2 x 106)
÷ (4 x 102)
(9 x 1012) ÷ (3 x 106)
(6 x 104) ÷ (2 x 10-5)
(3.5 x 10-4)÷ (7 x 10-6)
A piece of paper weighs 3 x 10-4g.
How much will 2.4 x 1012 pieces of paper weigh?
Work this out without a calculator.
Grade B – Calculating with Standard Form
Work these out without a calculator
6 x 1085)
(3
x (2 x 103)
2) x (5 x 108)
(3.2
1.6 x 1011
-5) x (2 x 10-2)
4.2 x 10-7
(2.1
3)11x (7 x 107)
4.2x x10
10
(6
(2
105-2) x (4 x 107)
8 xx10
3.2
10-5-8) x (4 x 10-4)
(8 xx10
Work these out without a calculator
(8
4 x 1069)
÷ (2 x 103)
3) ÷ (1.3 x 108)
-5
(2.6
x
10
2 x 10
5 x 1036) ÷ (4 x 102)
(2
(9
10612) ÷ (3 x 106)
3 xx 10
49) ÷ (2 x 10-5)
(63 xx 10
10
5 x x1010-4)÷ (7 x 10-6)
(3.5
A piece of paper weighs 3 x 10-4g.
How much will 2.4 x 1012 pieces of paper weigh?
Work this out without a calculator.
720000kg
```

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