Improve Tuition · Grade 2 · Percentages
Lesson · Practice · Steps

Percentages

Percent means "out of 100". Learn the shortcuts and build any percentage you need.

The six facts you need

Every percentage question uses one of these. You don't need to remember anything else.

1 · What % meansPercent means out of 100. So 50% = 50 out of 100 = 50/100 = ½.
2 · Common percentages50% = ½ · 25% = ¼ · 10% = 1/10 · 75% = ¾ · 20% = 1/5.
3 · % to decimalDivide by 100. Move the decimal point 2 places LEFT. So 45% = 0.45.
4 · Decimal to %Multiply by 100. Move the decimal point 2 places RIGHT. So 0.6 = 60%.
5 · Finding X% of amountUse shortcuts: 50% → ÷ 2, 25% → ÷ 4, 10% → ÷ 10.
6 · Building up30% = 10% × 3 · 15% = 10% + 5% · 5% = half of 10%.

Worked example 1 - 50% as a decimal

Convert 50% to a decimal.

50% = 50 out of 100
  1. Read it. Change 50% to a decimal.
  2. The fact. % means out of 100. So divide by 100.
  3. 50 ÷ 100 = 0.5.
  4. So 50% = 0.5 = ½.
Answer: 0.5
Watch outMove the decimal point 2 places LEFT. Not 1 place.

Worked example 2 - 25% as a decimal

Convert 25% to a decimal.

25% = 25 out of 100
  1. Read it. Change 25% to a decimal.
  2. The fact. % ÷ 100 = decimal.
  3. 25 ÷ 100 = 0.25.
  4. So 25% = 0.25 = ¼.
Answer: 0.25
Watch out25% = 0.25, NOT 2.5. Move TWO places left.

Worked example 3 - 0.7 as a percentage

Convert 0.7 to a percentage.

  1. Read it. Change 0.7 to a percentage.
  2. The fact. Multiply decimal by 100 to get %.
  3. 0.7 × 100 = 70.
  4. So 0.7 = 70%.
Answer: 70%
Watch out0.7 = 70% (not 7%). Move TWO places right.

Worked example 4 - 50% of 60

Find 50% of 60.

Total (100%) = 6050%0%25%50%75%100%50% of 60 = 30
  1. Read it. Find 50% of 60.
  2. The fact. 50% = ½. So divide by 2.
  3. 50% of 60 = 60 ÷ 2 = 30.
Answer: 30
Watch out50% means HALF. Just divide by 2.

Worked example 5 - 10% of 80

Find 10% of 80.

Total (100%) = 8010%0%25%50%75%100%10% of 80 = 8
  1. Read it. Find 10% of 80.
  2. The fact. 10% = 1/10. So divide by 10.
  3. 10% of 80 = 80 ÷ 10 = 8.
Answer: 8
Watch outTo find 10%, DIVIDE by 10. Do not multiply.

Worked example 6 - 25% of 40

Find 25% of 40.

Total (100%) = 4025%0%25%50%75%100%25% of 40 = 10
  1. Read it. Find 25% of 40.
  2. The fact. 25% = ¼. So divide by 4.
  3. 25% of 40 = 40 ÷ 4 = 10.
Answer: 10
Watch out25% is a quarter. Just divide by 4.

Worked example 7 - 30% of 50 (building up)

Find 30% of 50.

Building 30%10%10%10%30% = 10% + 10% + 10%
  1. Read it. Find 30% of 50.
  2. The fact. 30% = 10% × 3. Find 10% first, then multiply by 3.
  3. 10% of 50 = 50 ÷ 10 = 5.
  4. 30% = 10% × 3.
  5. 5 × 3 = 15.
Answer: 15
Watch outThe build-up method: 30% is THREE lots of 10%.

Worked example 8 - 15% of 200

Find 15% of 200.

Building 15%10%5%15% = 10% + 5%
  1. Read it. Find 15% of 200.
  2. The fact. 15% = 10% + 5%. And 5% = half of 10%.
  3. 10% of 200 = 200 ÷ 10 = 20.
  4. 5% of 200 = half of 20 = 10.
  5. 15% = 10% + 5% = 20 + 10 = 30.
Answer: 30
Watch outOnce you know 10%, you can build 5% (half), 15%, 20%, 25%, 30% and more.
Practice · Section A
What % means
% ↔ decimal conversions
Practice · Section B
Shortcuts
50%, 25%, 10%, 75% of an amount
Practice · Section C
Building up
30%, 15%, 20%, 40% — build from 10%

Ready for more? 100 questions

When you have done these 12, you are ready for the bigger practice paper.

It has 100 questions. They start very easy and get harder near the end. Every question is still Grade 2 — nothing harder. You can stop at any time and come back.

Open the 100-question paper →

It opens in this same place. The lesson stays open behind it.

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