Calculate 65% of 220
Worked Solution & Answer
Find 10% (divide by 10) and 1% (divide by 100), or multiply by the decimal multiplier.
e.g. 15% of 60 = 6 + 3 = 9
143
e.g. 15% of 60 = 6 + 3 = 9
143
Answer: 143
Percentages — Notes & Worked Examples Show / Hide
Explanation:
On a non-calculator paper, break percentages down into building blocks: find 10% (÷ 10), 1% (÷ 100), 5% (half of 10%), and 50% (÷ 2), then add them together. On a calculator paper, convert the percentage to a decimal (÷ 100) and multiply.
To increase or decrease an amount by a percentage in one step, use a decimal multiplier: add the percentage to 100% for an increase (e.g. +15% → × 1.15), or subtract from 100% for a decrease (e.g. −15% → × 0.85).
Example 1 (Non-calc): Decrease £240 by 15%.
Solution:
10% of 240 = 240 ÷ 10 = £24
5% of 240 = 24 ÷ 2 = £12
15% = £24 + £12 = £36
Decrease: £240 − £36 = £204
Answer: £204
Example 2 (Calc): Increase £460 by 17.5%.
Solution:
100% + 17.5% = 117.5%
Multiplier = 117.5 ÷ 100 = 1.175
£460 × 1.175 = 540.5
Write money with 2 decimal places:
Answer: £540.50
Calculate 7.5% of £80
£
Worked Solution & Answer
Find 10% (divide by 10) and 1% (divide by 100), or multiply by the decimal multiplier.
e.g. 15% of 60 = 6 + 3 = 9
£6
e.g. 15% of 60 = 6 + 3 = 9
£6
Answer: £ £6
Work out 60% of 70
Worked Solution & Answer
Here is a shape made of squares.
(a) Shade 45 of the shape. [1 mark]
(b) Write 0.7 as a percentage. [1 mark]
%
(c) Write these decimals in order of size.
Start with the smallest decimal.
0.49 0.459 0.4 0.049 0.14 [1 mark]
Start with the smallest decimal.
0.49 0.459 0.4 0.049 0.14 [1 mark]
Worked Solution & Answer
(a)
(4/5) × 20 = 16 squares B1
Answer (a): 16 squares shaded
(b)
0.7 × 100 = 70% B1
Answer (b): 70 %
(c)
0.049, 0.140, 0.400, 0.459, 0.490 B1
Answer (c): 0.049, 0.14, 0.4, 0.459, 0.49
Here are the types of sandwiches sold in a cafe last week.
(a) Work out the total number of sandwiches sold. [2 marks]
(b) Write 18 as a percentage of 56
Give your answer correct to the nearest whole number. [2 marks]
Give your answer correct to the nearest whole number. [2 marks]
%
Worked Solution & Answer
(a)
(56 ÷ 40) × 100 = 140 M1 A1
Answer (a): 140
(b)
(18 ÷ 56) × 100 = 32.14...% → 32% M1 A1
Answer (b): 32 %
Work out
(a) Write 12/15 as a fraction in its simplest form. (1)
(b) Shade 1/6 of the shape below. (1)
(c) Write 1/5 as a decimal. (1)
(d) Write 7/10 as a percentage. (1)
(a) Write 12/15 as a fraction in its simplest form. (1)
(b) Shade 1/6 of the shape below. (1)
(c) Write 1/5 as a decimal. (1)
(d) Write 7/10 as a percentage. (1)
(a) Write 1215 as a fraction in its simplest form. [1 mark]
(b) Shade 16 of the shape below. [1 mark]
(c) Write 15 as a decimal. [1 mark]
(d) Write 710 as a percentage. [1 mark]
%
Worked Solution & Answer
(a)
Divide numerator and denominator by 3: 12/15 = 4/5 B1
Answer (a): 45
(b)
18 ÷ 6 = 3 squares shaded B1
Answer (b): 3 squares shaded
(c)
1 ÷ 5 = 0.2 B1
Answer (c): 0.2
(d)
7/10 = 70/100 = 70% B1
Answer (d): 70 %
(a) Write 23/100 as decimal (1) (b) Write 0.7 as percentage (1) (c) Write 1/5 as decimal (1) (d) Shade 75% of octagon (1) (e) 21% asleep, percentage not asleep (1)
(a) Write 23100 as a decimal. [1 mark]
(b) Write 0.7 as a percentage. [1 mark]
%
(c) Write 15 as a decimal. [1 mark]
(d) Shade 75% of this diagram. [1 mark]
(e) What percentage of the people on the train are not asleep? [1 mark]
%
Worked Solution & Answer
(a)
0.23
Answer (a): 0.23
(b)
70
Answer (b): 70 %
(c)
0.2
Answer (c): 0.2
(d)
75% of 8 = 6 sectors B1
Answer (d): 6 of the 8 triangles shaded
(e)
100 − 21 = 79% B1
Answer (e): 79 %
(a) Order 7.831, 7.04, 7.002, 7.9, 7.013 (1) (b) 7% as decimal (1) (c) 0.47 as fraction (1) (d) 0.63 as % (1) (e) 0.003 × □ = 9 (1)
(a) Write these decimals in order of size.
Start with the smallest decimal.
7.831 7.04 7.002 7.9 7.013 [1 mark]
Start with the smallest decimal.
7.831 7.04 7.002 7.9 7.013 [1 mark]
(b) Write 7% as a decimal. [1 mark]
(c) Write 0.47 as a fraction. [1 mark]
(d) Write 0.63 as a percentage. [1 mark]
%
(e) Write a number in the box to make the calculation correct. [1 mark]
Worked Solution & Answer
(a)
7.002, 7.013, 7.04, 7.831, 7.9
Answer (a): 7.002, 7.013, 7.04, 7.831, 7.9
(b)
0.07
Answer (b): 0.07
(c)
47100
Answer (c): 47100
(d)
63
Answer (d): 63 %
(e)
3000
Answer (e): 3000
Work out
(a) 9/10 as decimal (1) (b) 3/50 as percentage (1) (c) Shade 5/8 of 24-square grid (1) (d) Fraction not equivalent to 2/5 (1) (e) Simplest fraction not studying French (2)
(a) 9/10 as decimal (1) (b) 3/50 as percentage (1) (c) Shade 5/8 of 24-square grid (1) (d) Fraction not equivalent to 2/5 (1) (e) Simplest fraction not studying French (2)
(a) Write 910 as a decimal. [1 mark]
(b) Write 350 as a percentage. [1 mark]
%
(c) Shade 58 of the shape. [1 mark]
(d) One of these fractions is **not** equivalent to 25
Which one?
2050 410 2500 1025 60150 [1 mark]
Which one?
2050 410 2500 1025 60150 [1 mark]
(e) What fraction of the students do **not** study French?
Give your fraction in its simplest form. [2 marks]
Give your fraction in its simplest form. [2 marks]
Worked Solution & Answer
(a)
0.9
Answer (a): 0.9
(b)
6
Answer (b): 6 %
(c)
5/8 × 24 = 15 squares B1
Answer (c): 15 squares shaded
(d)
2500
Answer (d): 2500
(e)
(32 − 8)/32 = 24/32 = 3/4 M1 A1
Answer (e): 34
Here is a shape made of squares.
(a) Shade 35 of the shape. [1 mark]
(b) Which one of these fractions is not equivalent to 47?
4070 814 400700 1417 2035 [1 mark]
4070 814 400700 1417 2035 [1 mark]
(c) Write 310 as a percentage. [1 mark]
%
(d) Write 779 as a mixed number. [1 mark]
(e) What is the number? [2 marks]
Worked Solution & Answer
(a)
(3/5) × 20 = 12 B1
Answer (a): 12 squares shaded
(b)
1417
Answer (b): 1417
(c)
30
Answer (c): 30 %
(d)
77 = 8 × 9 + 5 → 8 5/9 B1
Answer (d): 859
(e)
(40 ÷ 5) × 6 = 48 M1 A1
Answer (e): 48