Math lesson plan · 5th grade (Year 6 in England) · 30 minutes
Find a missing edge from the volume
Geometry
CCSS 5.MD.C.5.BEngland: Y6 Measurement
Objective and success criteria
Students will: Find a missing edge from the volume.
- 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)
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)). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
- A box is 8 ft long, 8 ft wide and 3 ft high. What is its volume, in ft³? → 192Prompt: Volume = length × width × height.
- A fish tank has a volume of 72 cubic units and a base of 6 by 4 units. How many units high is it? → 3Prompt: Volume = base area × height.
- A box is 9 m long, 2 m wide and 7 m high. What is its volume, in m³? → 126Prompt: 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: Find a missing edge from the volume. 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 cuboid has a volume of 50 cm³. Its length is 5 cm and its width is 2 cm. What is its height?
- Step 1: 5 × 2 = 10
- Step 2: 50 ÷ 10 = 5
- Step 3: 5 cm
- Answer: 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 cuboid has a volume of 320 cm³. Its length is 8 cm and its width is 8 cm. What is its height? → 5Prompt: Volume = length × width × height.
- A fish tank has a base area of 40 dm² and holds 240 dm³ of water when full. How deep is the water when the tank is full, in dm? → 6Prompt: Volume = base area × height.
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 a volume of 216 cm³. Its length is 8 cm and its width is 3 cm. What is its height? → 9Prompt: Volume = length × width × height.
- A fish tank has a base area of 30 dm² and holds 300 dm³ of water when full. How deep is the water when the tank is full, in dm? → 10Prompt: Volume = base area × height.
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-5.
Free lesson plan from eurekami.com/lesson-plan-builder