GCSE Maths: Percentages of an amount (Higher)

Method. To find a percentage of an amount without a calculator, find 10% (divide by 10) or 1% (divide by 100) first. Then build up to the percentage you need.

1. Find 10%. 10% is one tenth, so divide the amount by 10 (each digit moves one place to the right).
   10% of 80 = 80 ÷ 10 = 8
2. Write the answer. Include the units.
   10% of 80 = 8

Check. Another way: 10% = 0.1 as a decimal, and 0.1 × 80 = 8. ✓

Watch out. 10% means divide by 10 once. Do not divide by 10 and then by 10 again.

Method. To find a percentage of an amount without a calculator, find 10% (divide by 10) or 1% (divide by 100) first. Then build up to the percentage you need.

1. Find 10%. 10% is one tenth, so divide the amount by 10 (each digit moves one place to the right).
   10% of 150 = 150 ÷ 10 = 15
2. Work out each part. Multiply to build up to the percentage you want.
   20% = 2 × 10% = 2 × 15 = 30
3. Write the answer. Include the units.
   20% of 150 = 30

Check. Another way: 20% = 0.2 as a decimal, and 0.2 × 150 = 30. ✓

Watch out. 10% means divide by 10 once. Do not divide by 10 and then by 10 again.

Method. To find a percentage of an amount without a calculator, find 10% (divide by 10) or 1% (divide by 100) first. Then build up to the percentage you need.

1. Find 10%. 10% is one tenth, so divide the amount by 10 (each digit moves one place to the right).
   10% of 240 = 240 ÷ 10 = 24
2. Work out each part. Multiply to build up to the percentage you want.
   30% = 3 × 10% = 3 × 24 = 72
3. Write the answer. Include the units.
   30% of 240 = 72

Check. Another way: 30% = 0.3 as a decimal, and 0.3 × 240 = 72. ✓

Watch out. 10% means divide by 10 once. Do not divide by 10 and then by 10 again.

Method. To find a percentage of an amount without a calculator, find 10% (divide by 10) or 1% (divide by 100) first. Then build up to the percentage you need.

1. Spot that 50% is a half. 50 out of 100 is the same as 1 out of 2.
   50% = 12
2. Halve the amount. To find a half, divide by 2.
   64 ÷ 2 = 32

Check. Another way: 50% = 0.5 as a decimal, and 0.5 × 64 = 32. ✓

Watch out. 10% means divide by 10 once. Do not divide by 10 and then by 10 again.

Method. To find a percentage of an amount without a calculator, find 10% (divide by 10) or 1% (divide by 100) first. Then build up to the percentage you need.

1. Spot that 25% is a quarter. 25 out of 100 is the same as 1 out of 4.
   25% = 14
2. Find a quarter of the amount. To find a quarter, divide by 4 (or halve twice).
   120 ÷ 4 = 30

Check. Another way: 25% = 0.25 as a decimal, and 0.25 × 120 = 30. ✓

Watch out. 10% means divide by 10 once. Do not divide by 10 and then by 10 again.

Method. To find a percentage of an amount without a calculator, find 10% (divide by 10) or 1% (divide by 100) first. Then build up to the percentage you need.

1. Find 10%. 10% is one tenth, so divide the amount by 10 (each digit moves one place to the right).
   10% of 200 = 200 ÷ 10 = 20
2. Work out each part. Multiply to build up to the percentage you want.
   5% = half of 10% = 20 ÷ 2 = 10
3. Write the answer. Include the units.
   5% of 200 = 10

Check. Another way: 5% = 0.05 as a decimal, and 0.05 × 200 = 10. ✓

Watch out. 10% means divide by 10 once. Do not divide by 10 and then by 10 again.

Method. To find a percentage of an amount without a calculator, find 10% (divide by 10) or 1% (divide by 100) first. Then build up to the percentage you need.

1. Split the percentage into easy parts. We can find 10% and 1% very quickly, so we build the percentage out of them.
   15% = 10% + 5%
2. Find 10%. 10% is one tenth, so divide the amount by 10 (each digit moves one place to the right).
   10% of £360 = £360 ÷ 10 = £36
3. Work out each part. Use the 10% or 1% you found.
   10% = £36
   5% = half of 10% = £36 ÷ 2 = £18
4. Add the parts together. The parts together make up the whole percentage.
   £36 + £18 = £54

Check. Another way: 15% = 0.15 as a decimal, and 0.15 × £360 = £54. ✓

Watch out. 10% means divide by 10 once. Do not divide by 10 and then by 10 again.

Method. To find a percentage of an amount without a calculator, find 10% (divide by 10) or 1% (divide by 100) first. Then build up to the percentage you need.

1. Split the percentage into easy parts. We can find 10% and 1% very quickly, so we build the percentage out of them.
   35% = 30% + 5%
2. Find 10%. 10% is one tenth, so divide the amount by 10 (each digit moves one place to the right).
   10% of £80 = £80 ÷ 10 = £8
3. Work out each part. Use the 10% or 1% you found.
   30% = 3 × 10% = 3 × £8 = £24
   5% = half of 10% = £8 ÷ 2 = £4
4. Add the parts together. The parts together make up the whole percentage.
   £24 + £4 = £28

Check. Another way: 35% = 0.35 as a decimal, and 0.35 × £80 = £28. ✓

Watch out. 10% means divide by 10 once. Do not divide by 10 and then by 10 again.

Method. To find a percentage of an amount without a calculator, find 10% (divide by 10) or 1% (divide by 100) first. Then build up to the percentage you need.

1. Spot that 75% is three quarters. 75 out of 100 is the same as 3 out of 4.
   75% = 34
2. Find one quarter. Divide by 4.
   £48 ÷ 4 = £12
3. Multiply by 3. Three quarters is three lots of one quarter.
   3 × £12 = £36

Check. Another way: 75% = 0.75 as a decimal, and 0.75 × £48 = £36. ✓

Watch out. 10% means divide by 10 once. Do not divide by 10 and then by 10 again.

Method. To find a percentage of an amount without a calculator, find 10% (divide by 10) or 1% (divide by 100) first. Then build up to the percentage you need.

1. Split the percentage into easy parts. We can find 10% and 1% very quickly, so we build the percentage out of them.
   12% = 10% + 2%
2. Find 10%. 10% is one tenth, so divide the amount by 10 (each digit moves one place to the right).
   10% of £250 = £250 ÷ 10 = £25
3. Find 1%. 1% is one hundredth, so divide the amount by 100 (each digit moves two places to the right).
   1% of £250 = £250 ÷ 100 = £2.50
4. Work out each part. Use the 10% or 1% you found.
   10% = £25
   2% = 2 × 1% = 2 × £2.50 = £5
5. Add the parts together. The parts together make up the whole percentage.
   £25 + £5 = £30

Check. Another way: 12% = 0.12 as a decimal, and 0.12 × £250 = £30. ✓

Watch out. 10% means divide by 10 once. Do not divide by 10 and then by 10 again.

Method. To find a percentage of an amount without a calculator, find 10% (divide by 10) or 1% (divide by 100) first. Then build up to the percentage you need.

1. Find 1%. 1% is one hundredth, so divide the amount by 100 (each digit moves two places to the right).
   1% of £450 = £450 ÷ 100 = £4.50
2. Work out each part. Multiply to build up to the percentage you want.
   2% = 2 × 1% = 2 × £4.50 = £9
3. Write the answer. Include the units.
   2% of £450 = £9

Check. Another way: 2% = 0.02 as a decimal, and 0.02 × £450 = £9. ✓

Watch out. 10% means divide by 10 once. Do not divide by 10 and then by 10 again.

Method. To find a percentage of an amount without a calculator, find 10% (divide by 10) or 1% (divide by 100) first. Then build up to the percentage you need.

1. Find 1%. 1% is one hundredth, so divide the amount by 100 (each digit moves two places to the right).
   1% of £7,600 = £7,600 ÷ 100 = £76
2. Write the answer. Include the units.
   1% of £7,600 = £76

Check. Another way: 1% = 0.01 as a decimal, and 0.01 × £7,600 = £76. ✓

Watch out. 10% means divide by 10 once. Do not divide by 10 and then by 10 again.

Method. To find a percentage of an amount without a calculator, find 10% (divide by 10) or 1% (divide by 100) first. Then build up to the percentage you need.

1. Split the percentage into easy parts. We can find 10% and 1% very quickly, so we build the percentage out of them.
   45% = 40% + 5%
2. Find 10%. 10% is one tenth, so divide the amount by 10 (each digit moves one place to the right).
   10% of 600 g = 600 g ÷ 10 = 60 g
3. Work out each part. Use the 10% or 1% you found.
   40% = 4 × 10% = 4 × 60 g = 240 g
   5% = half of 10% = 60 g ÷ 2 = 30 g
4. Add the parts together. The parts together make up the whole percentage.
   240 g + 30 g = 270 g

Check. Another way: 45% = 0.45 as a decimal, and 0.45 × 600 g = 270 g. ✓

Watch out. 10% means divide by 10 once. Do not divide by 10 and then by 10 again.

Method. To find a percentage of an amount without a calculator, find 10% (divide by 10) or 1% (divide by 100) first. Then build up to the percentage you need.

1. Find 10%. 10% is one tenth, so divide the amount by 10 (each digit moves one place to the right).
   10% of 30 m = 30 m ÷ 10 = 3 m
2. Work out each part. Multiply to build up to the percentage you want.
   90% = 9 × 10% = 9 × 3 m = 27 m
3. Write the answer. Include the units.
   90% of 30 m = 27 m

Check. Another way: 90% = 0.9 as a decimal, and 0.9 × 30 m = 27 m. ✓

Watch out. 10% means divide by 10 once. Do not divide by 10 and then by 10 again.

Method. To find a percentage of an amount without a calculator, find 10% (divide by 10) or 1% (divide by 100) first. Then build up to the percentage you need.

1. Find 10%. 10% is one tenth, so divide the amount by 10 (each digit moves one place to the right).
   10% of 250 ml = 250 ml ÷ 10 = 25 ml
2. Work out each part. Multiply to build up to the percentage you want.
   60% = 6 × 10% = 6 × 25 ml = 150 ml
3. Write the answer. Include the units.
   60% of 250 ml = 150 ml

Check. Another way: 60% = 0.6 as a decimal, and 0.6 × 250 ml = 150 ml. ✓

Watch out. 10% means divide by 10 once. Do not divide by 10 and then by 10 again.

Method. To find a percentage of an amount without a calculator, find 10% (divide by 10) or 1% (divide by 100) first. Then build up to the percentage you need.

1. Split the percentage into easy parts. We can find 10% and 1% very quickly, so we build the percentage out of them.
   8% = 5% + 3%
2. Find 10%. 10% is one tenth, so divide the amount by 10 (each digit moves one place to the right).
   10% of 400 kg = 400 kg ÷ 10 = 40 kg
3. Find 1%. 1% is one hundredth, so divide the amount by 100 (each digit moves two places to the right).
   1% of 400 kg = 400 kg ÷ 100 = 4 kg
4. Work out each part. Use the 10% or 1% you found.
   5% = half of 10% = 40 kg ÷ 2 = 20 kg
   3% = 3 × 1% = 3 × 4 kg = 12 kg
5. Add the parts together. The parts together make up the whole percentage.
   20 kg + 12 kg = 32 kg

Check. Another way: 8% = 0.08 as a decimal, and 0.08 × 400 kg = 32 kg. ✓

Watch out. 10% means divide by 10 once. Do not divide by 10 and then by 10 again.

Method. To find a percentage of an amount without a calculator, find 10% (divide by 10) or 1% (divide by 100) first. Then build up to the percentage you need.

1. Find 10%. 10% is one tenth, so divide the amount by 10 (each digit moves one place to the right).
   10% of 3 km = 3 km ÷ 10 = 0.3 km
2. Work out each part. Multiply to build up to the percentage you want.
   70% = 7 × 10% = 7 × 0.3 km = 2.1 km
3. Write the answer. Include the units.
   70% of 3 km = 2.1 km

Check. Another way: 70% = 0.7 as a decimal, and 0.7 × 3 km = 2.1 km. ✓

Watch out. 10% means divide by 10 once. Do not divide by 10 and then by 10 again.

Method. To find a percentage of an amount without a calculator, find 10% (divide by 10) or 1% (divide by 100) first. Then build up to the percentage you need.

1. Split the percentage into easy parts. We can find 10% and 1% very quickly, so we build the percentage out of them.
   15% = 10% + 5%
2. Find 10%. 10% is one tenth, so divide the amount by 10 (each digit moves one place to the right).
   10% of 90 minutes = 90 minutes ÷ 10 = 9 minutes
3. Work out each part. Use the 10% or 1% you found.
   10% = 9 minutes
   5% = half of 10% = 9 minutes ÷ 2 = 4.5 minutes
4. Add the parts together. The parts together make up the whole percentage.
   9 minutes + 4.5 minutes = 13.5 minutes

Check. Another way: 15% = 0.15 as a decimal, and 0.15 × 90 minutes = 13.5 minutes. ✓

Watch out. 10% means divide by 10 once. Do not divide by 10 and then by 10 again.

Method. To find a percentage of an amount without a calculator, find 10% (divide by 10) or 1% (divide by 100) first. Then build up to the percentage you need.

1. Split the percentage into easy parts. We can find 10% and 1% very quickly, so we build the percentage out of them.
   35% = 30% + 5%
2. Find 10%. 10% is one tenth, so divide the amount by 10 (each digit moves one place to the right).
   10% of £80 = £80 ÷ 10 = £8
3. Work out each part. Use the 10% or 1% you found.
   30% = 3 × 10% = 3 × £8 = £24
   5% = half of 10% = £8 ÷ 2 = £4
4. Add the parts together. The parts together make up the whole percentage.
   £24 + £4 = £28

Check. Another way: 35% = 0.35 as a decimal, and 0.35 × £80 = £28. ✓

Watch out. 10% means divide by 10 once. Do not divide by 10 and then by 10 again.

Method. Take the reduction away from the original price.

1. Write down the original price and the reduction. The reduction was found in part (a).
   £80 and £28
2. Subtract. A sale price is lower than the original price.
   £80 − £28 = £52

Check. A 35% reduction leaves 65% of the price: 65% of £80 = 0.65 × 80 = £52. ✓

Watch out. Part (b) asks for the sale price, not the amount taken off.

Method. To find a percentage of an amount without a calculator, find 10% (divide by 10) or 1% (divide by 100) first. Then build up to the percentage you need.

1. Split the percentage into easy parts. We can find 10% and 1% very quickly, so we build the percentage out of them.
   45% = 40% + 5%
2. Find 10%. 10% is one tenth, so divide the amount by 10 (each digit moves one place to the right).
   10% of 800 = 800 ÷ 10 = 80
3. Work out each part. Use the 10% or 1% you found.
   40% = 4 × 10% = 4 × 80 = 320
   5% = half of 10% = 80 ÷ 2 = 40
4. Add the parts together. The parts together make up the whole percentage.
   320 + 40 = 360

Check. Another way: 45% = 0.45 as a decimal, and 0.45 × 800 = 360. ✓

Watch out. 10% means divide by 10 once. Do not divide by 10 and then by 10 again.

Method. The rest of the students are boys.

1. Write the number of girls. From part (a).
   Girls = 360
2. Subtract from the total. Everyone is either a girl or a boy.
   800 − 360 = 440

Check. Boys are 55% of 800 = 440. ✓

Watch out. Check that the two answers add up to the total.

Method. To find a percentage of an amount without a calculator, find 10% (divide by 10) or 1% (divide by 100) first. Then build up to the percentage you need.

1. Split the percentage into easy parts. We can find 10% and 1% very quickly, so we build the percentage out of them.
   15% = 10% + 5%
2. Find 10%. 10% is one tenth, so divide the amount by 10 (each digit moves one place to the right).
   10% of £1,600 = £1,600 ÷ 10 = £160
3. Work out each part. Use the 10% or 1% you found.
   10% = £160
   5% = half of 10% = £160 ÷ 2 = £80
4. Add the parts together. The parts together make up the whole percentage.
   £160 + £80 = £240

Check. Another way: 15% = 0.15 as a decimal, and 0.15 × £1,600 = £240. ✓

Watch out. 10% means divide by 10 once. Do not divide by 10 and then by 10 again.

Method. There are 12 months in a year, so multiply the monthly saving by 12.

1. Write the monthly saving. From part (a).
   £240
2. Multiply by 12. 12 months in a year.
   £240 × 12 = £2,880

Check. £240 × 10 = £2,400 and £240 × 2 = £480; £2,400 + £480 = £2,880. ✓

Method. To find a percentage of an amount without a calculator, find 10% (divide by 10) or 1% (divide by 100) first. Then build up to the percentage you need.

1. Find 10%. 10% is one tenth, so divide the amount by 10 (each digit moves one place to the right).
   10% of £1,200 = £1,200 ÷ 10 = £120
2. Work out each part. Multiply to build up to the percentage you want.
   2.5% = a quarter of 10% = £120 ÷ 4 = £30
3. Write the answer. Include the units.
   2.5% of £1,200 = £30

Check. Another way: 2.5% = 0.025 as a decimal, and 0.025 × £1,200 = £30. ✓

Watch out. 10% means divide by 10 once. Do not divide by 10 and then by 10 again.

Method. To find a percentage of an amount without a calculator, find 10% (divide by 10) or 1% (divide by 100) first. Then build up to the percentage you need.

1. Split the percentage into easy parts. We can find 10% and 1% very quickly, so we build the percentage out of them.
   12.5% = 10% + 2.5%
2. Find 10%. 10% is one tenth, so divide the amount by 10 (each digit moves one place to the right).
   10% of 640 = 640 ÷ 10 = 64
3. Work out each part. Use the 10% or 1% you found.
   10% = 64
   2.5% = a quarter of 10% = 64 ÷ 4 = 16
4. Add the parts together. The parts together make up the whole percentage.
   64 + 16 = 80

Check. Another way: 12.5% = 0.125 as a decimal, and 0.125 × 640 = 80. ✓

Watch out. 10% means divide by 10 once. Do not divide by 10 and then by 10 again.

Method. To find a percentage of an amount without a calculator, find 10% (divide by 10) or 1% (divide by 100) first. Then build up to the percentage you need.

1. Split the percentage into easy parts. We can find 10% and 1% very quickly, so we build the percentage out of them.
   7.5% = 5% + 2.5%
2. Find 10%. 10% is one tenth, so divide the amount by 10 (each digit moves one place to the right).
   10% of 920 = 920 ÷ 10 = 92
3. Work out each part. Use the 10% or 1% you found.
   5% = half of 10% = 92 ÷ 2 = 46
   2.5% = a quarter of 10% = 92 ÷ 4 = 23
4. Add the parts together. The parts together make up the whole percentage.
   46 + 23 = 69

Check. Another way: 7.5% = 0.075 as a decimal, and 0.075 × 920 = 69. ✓

Watch out. 10% means divide by 10 once. Do not divide by 10 and then by 10 again.

Method. To find a percentage of an amount without a calculator, find 10% (divide by 10) or 1% (divide by 100) first. Then build up to the percentage you need.

1. Find 1%. 1% is one hundredth, so divide the amount by 100 (each digit moves two places to the right).
   1% of 3,000 = 3,000 ÷ 100 = 30
2. Work out each part. Multiply to build up to the percentage you want.
   0.5% = half of 1% = 30 ÷ 2 = 15
3. Write the answer. Include the units.
   0.5% of 3,000 = 15

Check. Another way: 0.5% = 0.005 as a decimal, and 0.005 × 3,000 = 15. ✓

Watch out. 10% means divide by 10 once. Do not divide by 10 and then by 10 again.

Method. Write the percentage as a decimal, then multiply it by the amount.

1. Change the percentage into a decimal. Per cent means “out of 100”, so divide by 100.
   12% = 12 ÷ 100 = 0.12
2. Write the multiplication. To find a percentage of an amount, multiply the amount by the percentage written as a decimal (“of” means multiply).
   12% of 650 = 0.12 × 650
3. Work it out on the calculator. Type the multiplication in carefully.
   0.12 × 650 = 78

Check. Estimate: 10% of 650 is 65, so 12% is 1.2 lots of that: about 78.00. ✓

Watch out. Divide the percentage by 100 first. 8% is 0.08, not 0.8.

Method. Write the percentage as a decimal, then multiply it by the amount.

1. Change the percentage into a decimal. Per cent means “out of 100”, so divide by 100.
   35% = 35 ÷ 100 = 0.35
2. Write the multiplication. To find a percentage of an amount, multiply the amount by the percentage written as a decimal (“of” means multiply).
   35% of 840 = 0.35 × 840
3. Work it out on the calculator. Type the multiplication in carefully.
   0.35 × 840 = 294

Check. Estimate: 10% of 840 is 84, so 35% is 3.5 lots of that: about 294.00. ✓

Watch out. Divide the percentage by 100 first. 8% is 0.08, not 0.8.

Method. Write the percentage as a decimal, then multiply it by the amount.

1. Change the percentage into a decimal. Per cent means “out of 100”, so divide by 100.
   7% = 7 ÷ 100 = 0.07
2. Write the multiplication. To find a percentage of an amount, multiply the amount by the percentage written as a decimal (“of” means multiply).
   7% of 1,250 = 0.07 × 1,250
3. Work it out on the calculator. Type the multiplication in carefully.
   0.07 × 1,250 = 87.5

Check. Estimate: 10% of 1,250 is 125, so 7% is 0.7 lots of that: about 87.50. ✓

Watch out. Divide the percentage by 100 first. 8% is 0.08, not 0.8.

Method. Write the percentage as a decimal, then multiply it by the amount.

1. Change the percentage into a decimal. Per cent means “out of 100”, so divide by 100.
   18% = 18 ÷ 100 = 0.18
2. Write the multiplication. To find a percentage of an amount, multiply the amount by the percentage written as a decimal (“of” means multiply).
   18% of 2,400 = 0.18 × 2,400
3. Work it out on the calculator. Type the multiplication in carefully.
   0.18 × 2,400 = 432

Check. Estimate: 10% of 2,400 is 240, so 18% is 1.8 lots of that: about 432.00. ✓

Watch out. Divide the percentage by 100 first. 8% is 0.08, not 0.8.

Method. Write the percentage as a decimal, then multiply it by the amount.

1. Change the percentage into a decimal. Per cent means “out of 100”, so divide by 100.
   4.5% = 4.5 ÷ 100 = 0.045
2. Write the multiplication. To find a percentage of an amount, multiply the amount by the percentage written as a decimal (“of” means multiply).
   4.5% of 360 = 0.045 × 360
3. Work it out on the calculator. Type the multiplication in carefully.
   0.045 × 360 = 16.2

Check. Estimate: 10% of 360 is 36, so 4.5% is 0.45 lots of that: about 16.20. ✓

Watch out. Divide the percentage by 100 first. 8% is 0.08, not 0.8.

Method. Write the percentage as a decimal, then multiply it by the amount.

1. Change the percentage into a decimal. Per cent means “out of 100”, so divide by 100.
   62% = 62 ÷ 100 = 0.62
2. Write the multiplication. To find a percentage of an amount, multiply the amount by the percentage written as a decimal (“of” means multiply).
   62% of 85 = 0.62 × 85
3. Work it out on the calculator. Type the multiplication in carefully.
   0.62 × 85 = 52.7

Check. Estimate: 10% of 85 is 8.5, so 62% is 6.2 lots of that: about 52.70. ✓

Watch out. Divide the percentage by 100 first. 8% is 0.08, not 0.8.

Method. Write the percentage as a decimal, then multiply it by the amount.

1. Change the percentage into a decimal. Per cent means “out of 100”, so divide by 100.
   17.5% = 17.5 ÷ 100 = 0.175
2. Write the multiplication. To find a percentage of an amount, multiply the amount by the percentage written as a decimal (“of” means multiply).
   17.5% of £84.60 = 0.175 × £84.60
3. Work it out on the calculator. Type the multiplication in carefully.
   0.175 × £84.60 = £14.805
4. Round the answer. Give the answer to 2 decimal places (for money, to the nearest penny).
   £14.805 = £14.81

Check. Estimate: 10% of 84.6 is 8.46, so 17.5% is 1.75 lots of that: about 14.81. ✓

Watch out. Divide the percentage by 100 first. 8% is 0.08, not 0.8.

Method. Write the percentage as a decimal, then multiply it by the amount.

1. Change the percentage into a decimal. Per cent means “out of 100”, so divide by 100.
   23% = 23 ÷ 100 = 0.23
2. Write the multiplication. To find a percentage of an amount, multiply the amount by the percentage written as a decimal (“of” means multiply).
   23% of £149.99 = 0.23 × £149.99
3. Work it out on the calculator. Type the multiplication in carefully.
   0.23 × £149.99 = £34.4977
4. Round the answer. Give the answer to 2 decimal places (for money, to the nearest penny).
   £34.4977 = £34.50

Check. Estimate: 10% of 149.99 is 15.00, so 23% is 2.3 lots of that: about 34.50. ✓

Watch out. Divide the percentage by 100 first. 8% is 0.08, not 0.8.

Method. Write the percentage as a decimal, then multiply it by the amount.

1. Change the percentage into a decimal. Per cent means “out of 100”, so divide by 100.
   6.5% = 6.5 ÷ 100 = 0.065
2. Write the multiplication. To find a percentage of an amount, multiply the amount by the percentage written as a decimal (“of” means multiply).
   6.5% of £2,450 = 0.065 × £2,450
3. Work it out on the calculator. Type the multiplication in carefully.
   0.065 × £2,450 = £159.25

Check. Estimate: 10% of 2,450 is 245, so 6.5% is 0.65 lots of that: about 159.25. ✓

Watch out. Divide the percentage by 100 first. 8% is 0.08, not 0.8.

Method. Write the percentage as a decimal, then multiply it by the amount.

1. Change the percentage into a decimal. Per cent means “out of 100”, so divide by 100.
   3.2% = 3.2 ÷ 100 = 0.032
2. Write the multiplication. To find a percentage of an amount, multiply the amount by the percentage written as a decimal (“of” means multiply).
   3.2% of £19,500 = 0.032 × £19,500
3. Work it out on the calculator. Type the multiplication in carefully.
   0.032 × £19,500 = £624

Check. Estimate: 10% of 19,500 is 1,950, so 3.2% is 0.32 lots of that: about 624.00. ✓

Watch out. Divide the percentage by 100 first. 8% is 0.08, not 0.8.

Method. Round to numbers that are easy to use.

1. Round the numbers. 48% is close to 50% and £603 is close to £600.
   48% ≈ 50%,  £603 ≈ £600
2. Work out the estimate. 50% is a half.
   £600 ÷ 2 = £300

Check. The estimate should be close to the exact value found in part (b). ✓

Watch out. An estimate uses rounded numbers; it is not exact.

Method. Write the percentage as a decimal, then multiply it by the amount.

1. Change the percentage into a decimal. Per cent means “out of 100”, so divide by 100.
   48% = 48 ÷ 100 = 0.48
2. Write the multiplication. To find a percentage of an amount, multiply the amount by the percentage written as a decimal (“of” means multiply).
   48% of £603 = 0.48 × £603
3. Work it out on the calculator. Type the multiplication in carefully.
   0.48 × £603 = £289.44

Check. Estimate: 10% of 603 is 60.3, so 48% is 4.8 lots of that: about 289.44. ✓

Watch out. Divide the percentage by 100 first. 8% is 0.08, not 0.8.

Method. Write the percentage as a decimal, then multiply it by the amount.

1. Change the percentage into a decimal. Per cent means “out of 100”, so divide by 100.
   0.35% = 0.35 ÷ 100 = 0.0035
2. Write the multiplication. To find a percentage of an amount, multiply the amount by the percentage written as a decimal (“of” means multiply).
   0.35% of 82,000 = 0.0035 × 82,000
3. Work it out on the calculator. Type the multiplication in carefully.
   0.0035 × 82,000 = 287

Check. Estimate: 10% of 82,000 is 8,200, so 0.35% is 0.035 lots of that: about 287.00. ✓

Watch out. Divide the percentage by 100 first. 8% is 0.08, not 0.8.

Method. Write the percentage as a decimal, then multiply it by the amount.

1. Change the percentage into a decimal. Per cent means “out of 100”, so divide by 100.
   0.8% = 0.8 ÷ 100 = 0.008
2. Write the multiplication. To find a percentage of an amount, multiply the amount by the percentage written as a decimal (“of” means multiply).
   0.8% of £6,250 = 0.008 × £6,250
3. Work it out on the calculator. Type the multiplication in carefully.
   0.008 × £6,250 = £50

Check. Estimate: 10% of 6,250 is 625, so 0.8% is 0.08 lots of that: about 50.00. ✓

Watch out. Divide the percentage by 100 first. 8% is 0.08, not 0.8.