Math lesson plan · 4th grade (Year 5 in England) · 45 minutes
Convert metric lengths: km, m, cm and mm
Measurement
CCSS 4.MD.A.1England: Y5 Measurement
Objective and success criteria
Students will: Convert metric lengths: km, m, cm and mm.
- 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: Millimetres, centimetres and metres; Convert units of length, mass, capacity and time
Leads to: Approximate conversions between miles and kilometres
Materials: Rulers, scales and measuring jugs, Clock faces, Conversion chart, Mini whiteboards and pens, Printed student sheet (below).
Warm-up · 5 min
- Quick retrieval from earlier learning (Millimetres, centimetres and metres; Convert units of length, mass, capacity and time). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
- 7 cm = ? mm → 70Prompt: 1 cm = 10 mm and 1 m = 100 cm.
- 12 minutes = how many seconds? → 720Prompt: 1 minute = 60 seconds.
- A young tree is 2 m 54 cm tall. How tall is it in centimetres? → 254Prompt: 1 m = 100 cm.
Hook · 5 min
- Ask the class to estimate the length of the room or the weight of a bag before measuring it.
- Share the objective: Convert metric lengths: km, m, cm and mm. Read the success criteria together.
I do: model it · 10 min
- Work through the example out loud, saying why you do each step, not just what you do.
- Example: Write 3 km 822 m in metres.
- Step 1: 3 × 1000 + 822 = 3822
- Step 2: 3822 m
- Answer: 3822
- Pause after each step and ask a student to say what comes next.
We do: guided practice · 10 min
- Do these together. Students try each step on whiteboards before you reveal it.
- Use the hints as prompts rather than giving the answer.
- Write 3 km 312 m in metres. → 3312Prompt: 1 km = 1000 m.
- 31000 m = ? km → 31Prompt: A kilometre is 1000 m; a metre is 100 cm or 1000 mm.
You do: independent practice · 10 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 8 questions are on the student sheet below, with answers in the key.
Exit ticket · 5 min
- Two questions on their own. Sort answers into got it / nearly / not yet to plan the next lesson.
- Write 5 km 963 m in metres. → 5963Prompt: 1 km = 1000 m.
- 33 km = ? m → 33000Prompt: A kilometre is 1000 m; a metre is 100 cm or 1000 mm.
Watch out for
- Measuring from the end of the ruler instead of zero.
- Converting units the wrong way (multiplying instead of dividing).
Support and stretch
Support
- Review first: Millimetres, centimetres and metres.
- Use concrete materials: rulers, scales and measuring jugs.
- Give the first step of each question, or a partly worked example to finish.
- Pair with a confident partner for the guided practice.
Stretch
- Move on to: Approximate conversions between miles and kilometres.
- 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-4.
Free lesson plan from eurekami.com/lesson-plan-builder