π
θ
E = mc²
y = mx+b
Δ
φ
λ
HomeLessonsGrade 8
Grade 8 · Financial Maths · 15 min read

Percentages: The Complete Money-Maths Guide

Every percentage question in the Grade 8–9 syllabus — finding a percentage, increase and decrease, one number as a percentage of another, percentage change, VAT, profit and loss, and reverse percentages — each worked in full, with a worksheet.

A percentage is a fraction out of 100. Getting comfortable with percentages unlocks the whole financial-maths section: profit and loss, discounts, VAT and interest. This guide covers every percentage question type in the syllabus.

100% (the whole)60%40%e.g. 60% of R300 = R180
A percentage is part of a whole (100%). Here 60% is shaded, leaving 40%.

1Type 1: Finding a percentage of an amount

Change the percentage to a decimal (or fraction) and multiply.

Worked ExampleExample 1: find 15% of R80
  1. 1
    15% = 15⁄100 = 0,15.
    'Per cent' means 'out of 100'.
  2. 2
    0,15 × 80 = 12.
    'Of' means multiply.
  3. 3
    Answer: R12.

2Type 2: Percentage increase

Worked ExampleExample 2: increase R2000 by 30%
  1. 1
    Method A — find the increase: 30% of 2000 = 600, then add: 2000 + 600 = 2600.
    The increase is added to the original.
  2. 2
    Method B — multiply by 1,30 directly: 2000 × 1,30 = 2600.
    100% + 30% = 130% = 1,30.
  3. 3
    Answer: R2600.

3Type 3: Percentage decrease (discount)

Worked ExampleExample 3: a R250 jacket is discounted by 20%
  1. 1
    Discount: 20% of 250 = R50, then subtract: 250 − 50 = R200.
    A discount reduces the price.
  2. 2
    Shortcut: pay 80% → 0,80 × 250 = R200.
    After a 20% discount you pay 100% − 20% = 80%.

4Type 4: One number as a percentage of another

Write the part over the whole, then multiply by 100.

Worked ExampleExample 4: what percentage is 18 out of 24?
  1. 1
    Write the fraction: 18⁄24.
    Part over whole.
  2. 2
    Multiply by 100: 18⁄24 × 100 = 75.
    Convert the fraction to a percentage.
  3. 3
    Answer: 75%.

5Type 5: Percentage change (profit or loss %)

Percentage change = changeoriginal × 100. For profit and loss, the 'original' is the cost price.

Worked ExampleExample 5: bought for R80, sold for R100. Find the profit %
  1. 1
    Profit = 100 − 80 = R20.
    Selling price minus cost price.
  2. 2
    Percentage = 20⁄80 × 100 = 25%.
    Change over the ORIGINAL (cost) price.
  3. 3
    Answer: 25% profit.

6Type 6: VAT (Value-Added Tax, 15% in SA)

Worked ExampleExample 6: add 15% VAT to R600
  1. 1
    VAT = 15% of 600 = R90.
    VAT is added on top of the price.
  2. 2
    Total = 600 + 90 = R690, or 600 × 1,15 directly.

7Type 7: Reverse percentage (find the original)

When a price already includes an increase, divide (don't subtract) to get back to the original.

Worked ExampleExample 7: a price is R690 including 15% VAT. Find the price before VAT
  1. 1
    R690 represents 115% of the original.
    The original (100%) plus 15% VAT.
  2. 2
    Original = 690 ÷ 1,15 = R600.
    Divide by 1,15, don't subtract 15% — that would be wrong.
💡

Learn the ×1,15 / ÷1,15 shortcuts. Multiplying by 1 + rate does an increase in one step; dividing by it reverses one. This saves time and avoids errors under exam pressure.

⚠️

Adding then removing the same percentage doesn't cancel. R100 marked up 10% (R110) then discounted 10% gives R99, not R100 — the 10% is taken of different amounts each time.

Percentages run through Grade 8–12 financial maths and all of Maths Literacy, so these seven types are worth mastering completely. Try the worksheet.

Practice exercises

Work each one out, then click to reveal the answer.

  1. 1
    Find 25% of R320 (percentage of)
    Show answer ▾
    0,25 × 320 = R80
  2. 2
    Find 12% of 150 (percentage of)
    Show answer ▾
    0,12 × 150 = 18
  3. 3
    Increase R2000 by 30% (increase)
    Show answer ▾
    2000 × 1,30 = R2600
  4. 4
    Increase R450 by 8% (increase)
    Show answer ▾
    450 × 1,08 = R486
  5. 5
    Decrease R250 by 20% (decrease)
    Show answer ▾
    250 × 0,80 = R200
  6. 6
    A R900 item at 15% off (discount)
    Show answer ▾
    900 × 0,85 = R765
  7. 7
    What percentage is 18 out of 24? (as a %)
    Show answer ▾
    18⁄24 × 100 = 75%
  8. 8
    What percentage is 30 out of 40? (as a %)
    Show answer ▾
    30⁄40 × 100 = 75%
  9. 9
    Bought for R80, sold for R100. Profit %? (profit)
    Show answer ▾
    20⁄80 × 100 = 25%
  10. 10
    Bought for R200, sold for R150. Loss %? (loss)
    Show answer ▾
    50⁄200 × 100 = 25% loss
  11. 11
    Add 15% VAT to R240 (VAT)
    Show answer ▾
    240 × 1,15 = R276
  12. 12
    A price is R575 including 15% VAT. Price before VAT? (reverse)
    Show answer ▾
    575 ÷ 1,15 = R500
🧠

Quick Quiz

5 quick questions on what you just read. Take it when you feel ready.

Now practise it

Download Grade 8 past papers and worksheets on this topic.

Go to Grade 8 papers →