Fractions, Percentages and Money: Year 5 Study Guide
Fractions, decimals and percentages are three ways of writing the same part of a whole.
Year 5 students compare and order fractions with related denominators (such as halves, quarters and eighths) and add and subtract them. They see that 1/2, 0.5 and 50% all name the same amount. A percentage means 'out of 100', so 25% = 25/100 = 1/4 = 0.25.
Money is an everyday use of decimals. Since Australia no longer has 1 and 2 cent coins, cash totals are rounded to the nearest 5 cents.
Equivalent forms
| Fraction | Decimal | Percentage |
|---|---|---|
| 1/2 | 0.5 | 50% |
| 1/4 | 0.25 | 25% |
| 3/4 | 0.75 | 75% |
| 1/10 | 0.1 | 10% |
| 1/5 | 0.2 | 20% |
Adding and subtracting fractions
If one denominator is a multiple of the other, change the smaller to match. 1/2 + 3/8 = 4/8 + 3/8 = 7/8. 5/6 − 1/3 = 5/6 − 2/6 = 3/6 = 1/2. Mixed numbers: 1 1/4 + 2 1/2 = 3 3/4 (add the wholes, then the fractions).
Is one a multiple of the other?
Make them the same.
Keep the denominator.
Divide top and bottom by the same number.
Money and rounding
Find 10% by dividing by 10, 50% by halving and 25% by halving twice. A $48 jacket with 25% off saves $12, so it costs $36. For cash purchases, the total is rounded to the nearest 5 cents: $7.82 becomes $7.80 and $7.83 becomes $7.85. Rounding only applies to the final total, not to each item. Card payments are not rounded.
Worked examples and common mistakes
Example: Find 15% of $60: 10% is $6, 5% is $3, so 15% is $9. Common mistakes: adding denominators (1/4 + 1/4 is not 2/8), thinking 10% of an amount means dividing by 100, and rounding every item instead of the total. Estimate first to check.
Check your understanding: model answers
1. 5/8 + 2/8 = 7/8. 2. $20. 3. $12.45.
✨ Key Takeaways
- 1/2 = 0.5 = 50%.
- Rewrite fractions so denominators match.
- 10% means dividing by 10.
- Cash totals round to the nearest 5 cents.
💬 Questions for Discussion & Reflection
- Work out 5/8 + 1/4.
- Find 25% of $80.
- Round $12.43 to the nearest 5 cents.
Print a fractions equivalence chart →