Watch out
Choosing a method from a remembered keyword instead of reading the whole question.
Back to National 5 Mathematics
SQA National 5 Mathematics
Fractions, decimals and percentages review
Converting between forms and using percentage change accurately.
Formula reference
Check the National 5 rules and formulae linked to this topic.
Which method?
Match exam clues to a suitable method.
Before you start
- Read the command word and identify what is being asked.
- Write down the relevant formula, rule or algebraic structure before substituting values.
- Keep working set out line by line so method marks are clear.
Explanation
Fractions, decimals and percentages review is part of Number and Algebra in SQA National 5 Mathematics. The key skill is choosing a method and communicating the working clearly.
For fractions, decimals and percentages review, underline the values or algebraic terms you are given, choose the matching rule, then simplify one line at a time.
National 5 answers should show enough working for a marker to follow the method. Exact answers are expected where the question asks for exact form; otherwise round only at the end.
Key formulae and rules
- Calculator and non-calculator methods may both be useful.
Check
Compare your answer with the size you expected from the question.
Exam tip
Method marks come from clear setup and correct mathematical notation, not just a final answer.
Calculator tip
Use brackets for fractions, powers and square roots, then round only at the final line.
Worked examples
Worked example 1
Simplify an expression
Simplify 3x + 4x − 2.
- Collect like terms: 3x + 4x = 7x
- Keep the constant term −2.
Answer: 7x − 2.
Worked example 2
Solve an equation
Solve 5x − 7 = 18.
- Add 7 to both sides: 5x = 25
- Divide by 5.
So: x = 5
Worked example 3
Check the answer
Check x = 5 in 5x − 7 = 18
- 5(5) − 7 = 25 − 7
- 25 − 7 = 18
Answer: The solution checks correctly.
Watch out
- Choosing a method from a remembered keyword instead of reading the whole question.
- Dropping negative signs, powers or brackets during the working.
- Giving a rounded decimal when an exact answer or algebraic form is needed.