Math lesson plan · 6th grade (Year 7 in England) · 30 minutes
Volume of cuboids with fraction and decimal edges
Geometry
CCSS 6.G.A.2England: KS3 Geometry and measures
Objective and success criteria
Students will: Volume of cuboids with fraction and decimal edges.
- I can answer questions on today's skill on my own, without help.
- I can explain each step and say why it works.
- I can check my answer and spot a mistake.
Before and after
Needs first: Volume of cuboids (rectangular prisms); Multiply fractions
Leads to: the next skill in this area.
Materials: Rulers and protractors, Squared or dotted paper, Shape cut-outs, Mini whiteboards and pens, Printed student sheet (below).
Warm-up · 4 min
- Quick retrieval from earlier learning (Volume of cuboids (rectangular prisms); Multiply fractions). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
- A box is 9 ft long, 7 ft wide and 8 ft high. What is its volume, in ft³? → 504Prompt: Volume = length × width × height.
- A box is 9 m long, 7 m wide and 7 m high. What is its volume, in m³? → 441Prompt: Volume = length × width × height.
- A box is 6 ft long, 6 ft wide and 5 ft high. What is its volume, in ft³? → 180Prompt: Volume = length × width × height.
Hook · 3 min
- Show a photo of a building, a tile pattern or a road sign and ask what shapes and angles students can spot.
- Share the objective: Volume of cuboids with fraction and decimal edges. Read the success criteria together.
I do: model it · 7 min
- Work through the example out loud, saying why you do each step, not just what you do.
- Example: A box measures 2.5 cm by 3 cm by 3 cm. What is its volume, in cm³?
- Step 1: 2.5 × 3 = 7.5
- Step 2: 7.5 × 3 = 22.5 cm³
- Answer: 22.5
- Pause after each step and ask a student to say what comes next.
We do: guided practice · 6 min
- Do these together. Students try each step on whiteboards before you reveal it.
- Use the hints as prompts rather than giving the answer.
- A box measures 5.4 cm by 8 cm by 0.5 cm. What is its volume, in cm³? → 21.6Prompt: Volume = length × width × height.
- A cuboid has edges 2/3 m, 2 m and 3 m. Find its volume in m³ as a fraction or mixed number. → 4Prompt: Write every edge as a fraction.
You do: independent practice · 7 min
- Students work on the student sheet. Circulate and check the first two answers of every student early.
- Students who finish: write a question of their own for a partner, with the answer.
The 6 questions are on the student sheet below, with answers in the key.
Exit ticket · 3 min
- Two questions on their own. Sort answers into got it / nearly / not yet to plan the next lesson.
- A cuboid has edges 1/2 m, 6 m and 1/2 m. Find its volume in m³ as a fraction or mixed number. → 3/2 (1 1/2)Prompt: Write every edge as a fraction.
- How many cubes with edge ½ cm fill a box that is 2 cm by 2.5 cm by 3 cm? → 120Prompt: How many ½ cm cubes fit along each edge?
Watch out for
- Thinking a square turned on its corner is no longer a square.
- Reading the wrong scale on a protractor.
Support and stretch
Support
- Review first: Volume of cuboids (rectangular prisms).
- Use concrete materials: rulers and protractors.
- Give the first step of each question, or a partly worked example to finish.
- Pair with a confident partner for the guided practice.
Stretch
- Explain a common mistake in writing and how to fix it.
- Write a word problem that uses today's skill, then solve a partner's.
Homework and more practice
Free online practice with hints and printable worksheets for this skill: eurekami.com/math/grade-6.
Free lesson plan from eurekami.com/lesson-plan-builder