Year 7 · Number · original lesson pack
DASKEREL beta · internal AI review pending
Checking understanding of addition and subtraction with fractions
Open this lesson's library recordOfficial curriculum or provision guidance
DASKEREL wrote this teaching and practice using Oak's sequence as a source. View the source lesson at Oak National Academy. Oak has not endorsed this material. Check Oak's terms and separate rights for third-party works.
Learning outcomes
- Explain why equal-sized parts are needed
- Use equivalent fractions to add and subtract
Vocabulary: numerator · denominator · equivalent fraction · common denominator
Retrieve previous learning
Write 1/4 in eighths.
Check: 1/4 = 2/8. Both numerator and denominator are doubled, so the value is unchanged.
Learn the concept
The denominator names the size of a part. To combine 3/8 and 1/4, first rename 1/4 as 2/8. Now 3/8 + 2/8 = 5/8: five parts, each one eighth of the whole.
Subtraction uses the same equal-part principle. For 5/6 − 1/4, use twelfths: 5/6 = 10/12 and 1/4 = 3/12. Removing three twelfths leaves 7/12. The denominator stays 12 because the answer still counts twelfth-sized parts.
Choose a common multiple of both denominators; the lowest common multiple usually makes the calculation shorter. Check size: adding positive fractions makes a larger quantity, while subtracting a smaller positive fraction makes a smaller one.
Worked model
- Find 2/3 + 1/6 and choose sixths as the common-sized parts.
- Rename 2/3 as 4/6 by multiplying its numerator and denominator by two.
- Add equal-sized parts: 4/6 + 1/6 = 5/6.
- Check that the total is larger than 2/3 but less than one.
Guided practice
Calculate 3/4 − 1/8.
Hint: Rename quarters as eighths.
Check the guided answer
3/4 = 6/8, so 6/8 − 1/8 = 5/8.
Independent practice
Write your own response to every question before viewing the model answers. Your writing stays in this page session; this activity does not submit, store or grade it. Avoid including private information.
Find and correct a misconception
“3/8 + 1/4 = 4/12 because both the tops and bottoms should be added.”
Correction: Adding denominators changes part size. Rename 1/4 as 2/8, giving 3/8 + 2/8 = 5/8.
Extend and reflect
Find two different pairs of fractions with unequal denominators summing to 5/6.
Guidance: One is 1/2 + 1/3. Build another pair by working in twelfths or eighteenths and prove it.
Where this lesson could lead · Mathematics GCSE → Daskerel Mathematical Sciences
This lesson practises: Explain why equal-sized parts are needed. Quantitative reasoning supports later mathematical, data and engineering study.
- Next school subject: Mathematics GCSE. Check the subject and examination board that fit your school.
- Later DASKEREL learning: Daskerel Mathematical Sciences. Explore further study and build evidence from practical work.
- Later credential exploration: No subject-specific professional credential is mapped from this lesson. Explore the credential catalogue after choosing a later specialism.
- Example career direction: Quantitative Analyst. Explore organisations and local support.
This is an exploratory route, not a promise of admission, a qualification, certification eligibility or employment. Years 7–9 learning is an early foundation; any later credential may require substantial study, experience or local approval.