Units and measures – Year 9 maths lesson
Lesson 7 of 38 in the Year 9 maths course
UK version. UK school years, UK spelling and pounds (£). · US Math Department
A complete 45-minute lesson for Year 9 (ages 13–14) that runs on this page – at school or at home. Every answer is marked straight away, with a worked explanation.
- Time
- 45 minutes + 20 min homework
- Year
- Year 9 (ages 13–14)
- You need
- Paper, a pencil and this page
- Marked
- Instantly, with explanations
For parents: how to use this lesson
You don't need to know this topic yourself. The lesson explains each step on screen, one tidy step at a time. Every answer is marked straight away with a worked explanation, so you never have to mark anything.
- Read what your child will learn and the big ideas together.
- Press Start the lesson below and sit with your child for the teaching and the worked examples (about 19 minutes).
- Let them do the practice on their own. They choose Getting started, On track or Challenge – start on On track and move up after a few right in a row.
- Finish with the exit ticket and the talk question: “Why is 1 m² equal to 10,000 cm² and not 100 cm²?”
- Later that day or the next day: the homework (20 minutes), then a practice test.
Watch out for
- Using 100 for square centimetres in a square metre. Draw the square: 100 cm by 100 cm is 10,000 cm².
- Dividing when converting to a smaller unit. More of a smaller unit: multiply.
Tip for home: Convert recipe amounts or road distances between units.
What your child will learn
We are learning to convert between units of length, area, volume, time and money.
Success looks like
- I can convert lengths, masses and capacities.
- I can convert areas and volumes.
- I can convert between metric and imperial units.
Key words
- convert
- change to another unit
- metric
- units based on powers of 10
- imperial
- older units such as inches, feet and miles
- conversion factor
- the number you multiply by
What to have ready
- Paper and a pencil
- This page on a computer, tablet or phone
- For the hands-on part: Measure a table in centimetres and metres and work out its area in both units.
The big ideas (for the adult)
Use the conversion fact as a multiplier: 1 inch ≈ 2.54 cm, so 10 inches ≈ 25.4 cm.
For area, square the length conversion: 1 m² = 100 × 100 = 10,000 cm². For volume, cube it: 1 m³ = 1,000,000 cm³.
Ask whether the answer should be bigger or smaller: converting to a smaller unit gives a bigger number.
The lesson, step by step
| Part | Time | How it is checked |
|---|---|---|
| Starter: quick recall | 5 min | Marked by Classfern |
| Teaching input | 10 min | Not assessed, self-checked |
| Worked examples and guided practice | 9 min | Not assessed, marked by Classfern |
| Independent practice | 15 min | Marked by Classfern |
| Plenary and exit ticket | 6 min | Marked by Classfern, self-checked |
Starter, "your turn", practice and exit ticket are marked by Classfern. Worked examples and teaching are not assessed. The hands-on task and the reflection are self-assessed. Explanations in talk are judged by the parent and not recorded.
The lesson
It runs here on the page. No sign-up and no names – progress is kept only in this browser.
Homework and practice at home
20 minutes: 10 practice questions, 3 multiple-choice questions and 2 to remember from earlier work, then a short reflection. New questions every time, all marked instantly.
More practice
More Year 9 maths lessons
- Prime factors, HCF and LCM
- Rounding and estimation
- Bounds and error intervals
- Standard form
- Laws of indices
- Powers and roots
- Area of triangles, parallelograms and trapeziums
- Circles: circumference, area, arcs and sectors
- Volume and surface area
- Angle facts and parallel lines
- Angles in polygons
- Pythagoras' theorem
- Trigonometry: SOH CAH TOA
- Transformations
- Similarity and congruence
- Quadrilaterals and symmetry
- Coordinate geometry
- 3-D shapes, plans and elevations
- Quartiles, box plots and spread
- Pie charts and time series graphs
- Sampling
- Relative frequency and expected outcomes
- Venn diagrams and conditional probability
- Algebraic notation
- Substitution
- Simplifying expressions
- Expanding brackets
- Solving linear equations
- Inequalities
- Rearranging formulae
- Sequences and the nth term
- Straight-line graphs
- Graphs of functions
- Ratio
- Percentages
- Speed, density and pressure
- Scale drawings and maps
Curriculum
National Curriculum for England, Year 9: “change freely between related standard units [for example time, length, area, volume/capacity, mass]”
GCSE subject content G14: “use standard units of measure and related concepts (length, area, volume/capacity, mass, time, money, etc.)”
Contains public sector information licensed under the Open Government Licence v3.0.
Our lessons and questions are our own. They are not written or endorsed by any government department, testing agency or exam board.