GCSE Maths - Year 1 Week 9
Week 9: Understanding Ratio
Welcome to Unit 3, Ratio & Proportion. This week is all about ratio: what it means, how to simplify it, how to share an amount using one, and how to solve problems when you're only given part of the picture. Ratio shows up constantly in real life: recipes, paint mixing, map scales, exchange rates, so this is a genuinely practical unit.
Same shape as always: warm-up, teach, practice (Foundation, Intermediate or Higher — pick one), mark, exit ticket.
Monday — Understanding & Simplifying Ratios
What you're learning: What a ratio actually represents, how to write one correctly, and how to simplify a ratio to its lowest terms, the same idea as simplifying a fraction.
Warm-up (5 min): Corbett Maths 5-a-day (GCSE) — general mixed recall.
Teach (10 min): Watch:
Corbett Maths — Ratio Videos (start with "Ratio: Simplifying")
A ratio compares quantities of the same kind. To simplify one, divide every part by their highest common factor, exactly the HCF skill from Unit 1.
Practice (20 min): Pick one path:
Foundation: Transum — Ratio, Level 1.
Intermediate: Maths Genie — Writing and Simplifying Ratio, one worksheet (a different style of question set to Corbett's).
Higher: Corbett Maths — Exam Style Questions on Ratio (the longer piece) plus Transum — Ratio, a harder level.
Mark & fix: Check, correct, and note why for anything you got wrong.
Exit ticket: Simplify the ratio 24:36 fully. Show which number you divided by.
Tuesday — Sharing in a Given Ratio
What you're learning: How to split an amount into parts according to a given ratio, a skill that comes up everywhere from splitting a bill to mixing concrete.
Warm-up (5 min): Transum — Ratio, Level 1 — recall of yesterday.
Teach (10 min):
Corbett Maths — Ratio: Sharing the Total (on the Ratio Videos page)
Method: add up the parts of the ratio to find the total number of shares, divide the amount by that total to find the value of one share, then multiply back up for each part.
Practice (20 min): Pick one path:
Foundation: Transum — Ratio, Level 2, focusing on sharing-style questions.
Intermediate: Corbett Maths — Ratio: Sharing the Total, one page.
Higher: Corbett Maths — Ratio: Given One Quantity as many as you can complete in 20 mins, plus Khan Academy — Ratios, rates, proportions, equivalent ratios and quiz 2.
Mark & fix: As before — the most common mistake here is dividing by the number of parts in the ratio (e.g. 2) instead of the total number of shares (e.g. 2+3=5), so double-check what you divided by.
Exit ticket: Share £45 in the ratio 2:3:4. Show the value of one share before working out each part.
Wednesday — Ratio Problems: Given One Quantity
What you're learning: How to solve ratio problems when you're told the value of just one part, rather than the total, working out the value of one share first, then scaling to find everything else.
Warm-up (5 min): Corbett Maths 5-a-day (GCSE) — general mixed recall.
Teach (10 min):
Corbett Maths — Ratio: Given One Quantity (on the Ratio Videos page)
Practice (20 min): Pick one path:
Foundation: Khan Academy — Ratios, rates, proportions, from the top to Quiz 1.
Intermediate: Corbett Maths — Ratio: Given One Quantity, one page.
Higher: Corbett Maths — Ratio: Problem Solving (the longer piece, multi-step exam-style questions) plus Transum — Unitary Method, harder questions.
Mark & fix: As before.
Exit ticket: In a fruit bowl, the ratio of apples to oranges is 3:5. There are 9 apples. How many oranges are there? Show your method.
Thursday — Combining Ratios & Ratio as a Fraction
What you're learning: How to combine two separate ratios that share a common quantity into one three-part ratio, and how to express a ratio as a fraction or percentage of the whole.
Quick note before today's video: writing a ratio as a fraction leans on understanding what a fraction actually represents (a part out of a whole). We haven't covered fractions as their own topic yet in this course, that's coming later, so if fractions still feel unfamiliar, take a look at Khan Academy — Algebra Basics: Fractions first. You don't need to be an expert, just comfortable with the basic idea, before today's second half.
Warm-up (5 min): Corbett Maths — Ratio: Given One Quantity, first few questions — recall of yesterday.
Teach (10 min):
Corbett Maths — Ratio: Two Ratios and Ratio: Expressing as a Fraction/Percentage (both on the Ratio Videos page)
To combine two ratios like 3:2 and 2:5 (where the "2" refers to the same thing in both), scale each ratio so that shared quantity matches in both, then merge them into one three-part ratio.
Practice (20 min): Pick one path:
Foundation: Transum — Ratio vs Fractions, the introductory questions.
Intermediate: Corbett Maths — Ratio: Two Ratios, one page.
Higher: Corbett Maths — Ratio: Expressing as a Fraction/Percentage (the longer piece) plus Transum — Ratio vs Fractions, the harder questions.
Mark & fix: As before.
Exit ticket: The ratio of red to blue counters is 3:5. What fraction of the counters are blue? What percentage is that?
Friday — Consolidation
Today's not about new content, it's about locking in this week's ideas.
Quiz (10–15 min): Transum — Ratio, mixed levels.
Weekend printable : MEP Year 8 Practice Book — Unit 7: Ratio and Proportion (PDF), 7.1.
End-of-week reflection (5 min): In your notebook, answer:
Which topic this week felt most solid?
Which topic do you want to see again before we move on?
Rate your confidence 1–5 on: simplifying ratios, sharing in a ratio, ratio problems with one quantity given, combining ratios/ratio as a fraction.
Keep this reflection — we'll circle back to anything you flagged as shaky in the mixed-review session at the end of Unit 3 (Week 11).
Next week: Direct proportion, best buys, scale drawings, and unit conversion, putting ratio to work in real-world contexts.
