You will learn
- Read a measurement problem.
- Add or subtract measurements in the same unit.
- Change units when needed.
- Write the answer with its unit.
Version 0.1 · published for early use · expert review pending Standards alignment: pending verification. Not yet reviewed against the Courseversity scorecard.
Student lesson
Words to know
What we measure in, like cm, kg, L.
All of them added together.
What remains.
Change from one unit to another.
1. Discover: cloth, rice and water
A seller has 100 cm of ribbon and cuts off 35 cm. How much ribbon is left?
2. Understand: measurement problems
Read the problem, find the unit, and decide to add or subtract.
100 cm − 35 cm = 65 cm. A rope of 3 m and a rope of 2 m together: 3 + 2 = 5 m. 4 jugs of 2 L: 4 × 2 = 8 L. 5 kg − 2 kg = 3 kg.
If the units are different, change them first: 1 m = 100 cm, 1 kg = 1,000 g, 1 L = 1,000 ml. Always write the unit in the answer.
3. Explore: problem time
You need paper and a pencil.
- Read: ribbon 100 cm, cut 35 cm.
- Write 100 − 35.
- Solve: 65.
- Write: 65 cm left.
Think about it: what did you notice?
65 cm of ribbon is left.
4. Practise
Guided practice
Question 1. 100 cm − 35 cm?
65 cm.
Question 2. 3 m + 2 m?
5 m.
Question 3. 4 jugs of 2 L?
4 × 2 = 8 L.
Independent practice
- A rope 3 m and 2 m together
- Rice 5 kg, 2 kg used. Left?
- 3 jugs of 2 L. Total?
- Ribbon 1 m, 40 cm used. Left in cm?
- A tank has 20 L, 4 L used, then 6 L added. How many litres?
Answers are in the answer key below. Try first, then check.
5. Apply: everyday mathematics
A tank has 20 L. 4 L is used, then 6 L is added. How many litres now?
Show a sample answer
22 L.
6. Common mistake
Fix: Write the unit with the number.
7. Check and master
Answer all questions. You will see feedback after each one.
Your result appears here after you answer every question.
8. Key takeaways
- Use the same unit.
- Add or subtract.
- Write the unit.
9. Next lesson
Next lesson: Reading clocks. Keep going with the next idea in this course.
Printable worksheet
- 3 m + 2 m
- 5 kg − 2 kg
- 3 jugs of 2 L
- 1 m − 40 cm in cm
- 20 L − 4 L + 6 L
Homework
Write a measurement problem about home (cloth, rice or water) and solve it.
Answer key and marking scheme
| Question | Expected response | Marks |
|---|---|---|
| 3 m + 2 m | 5 m | 2 |
| 5 kg − 2 kg | 3 kg | 2 |
| 3 jugs of 2 L | 6 L | 2 |
| 1 m − 40 cm in cm | 60 cm | 2 |
| 20 L − 4 L + 6 L | 22 L | 2 |
| Total | 10 |
Practice answers: Worksheet: 1 5 m; 2 3 kg; 3 6 L; 4 60 cm; 5 22 L.
Quiz answers: 1 A, 2 B, 3 C, 4 A, 5 B, challenge C.
Mastery and remediation
| Objective | Bronze (Developing) | Silver (Proficient) | Gold (Advanced) |
|---|---|---|---|
| O1 Read a measurement problem | Shows this with help from an adult or a picture | Does this independently and explains how they know | Explains it clearly and uses it in a new situation |
| O2 Add or subtract measurements in the same unit | Shows this with help from an adult or a picture | Does this independently and explains how they know | Explains it clearly and uses it in a new situation |
| O3 Change units when needed | Shows this with help from an adult or a picture | Does this independently and explains how they know | Explains it clearly and uses it in a new situation |
| O4 Write the answer with its unit | Shows this with help from an adult or a picture | Does this independently and explains how they know | Explains it clearly and uses it in a new situation |
Proposed Courseversity thresholds for this page: Bronze = at least 3 of 5 core questions correct; Silver = all 5; Gold = all 5 plus the challenge. A badge is never a full record of progress.
If a learner struggles
- Find the misconception: Forgetting the unit in the answer. Write the unit with the number.
- Explain another way: use real objects first, then pictures.
- Show a simpler example: Use a bar model for each step.
- Guided practice: work through one example together and let the learner try the next one.
- Reassess: use the quiz again or the worksheet.
- Move on when the learner shows Silver-level evidence independently.
Teacher package
1–5. Objectives, prerequisites, materials, preparation, duration
Lesson objectives. Learners will: read a measurement problem; add or subtract measurements in the same unit; change units when needed; write the answer with its unit.
Prerequisite knowledge. Lessons 1 to 6.
Materials. Counters (stones, seeds or bottle tops), paper, pencils, board or chalkboard. Low-resource options: use stones, seeds, sticks, bottle tops or drawings in the sand or on the board instead of printed materials.
Preparation. Gather the counters and draw the example pictures on the board before the lesson.
Suggested duration. 35–45 minutes.
6–9. Teaching procedure, explanation notes, guided and independent activities
Introduction (5 min). Start with the Discover situation and let learners suggest ideas before you teach.
Explanation (10 min). Teach the Understand section with real objects first, then pictures, then symbols and words.
Guided activity (10 min). You need paper and a pencil. Learners follow the Explore steps in pairs.
Independent activity (10 min). Learners complete the independent practice and the worksheet.
Assessment and reflection (5 min). Ask each learner to say one thing they learned and how they know it.
Teacher explanation notes. Use the concrete, pictorial, abstract order: real objects first, then pictures, then symbols and words. Return to real objects whenever a learner needs support.
10–12. Differentiation, formative assessment, common misconceptions
Support. Use real objects and work with a partner; say each step aloud together. Extension. Ask learners to make up their own example and explain it to a partner.
Formative assessment. Listen to learner explanations, ask “how do you know?”, and check the independent work.
Misconceptions. Forgetting the unit in the answer. Write the unit with the number.
13–15. Assessment questions, answer keys, marking scheme
Use the quiz and worksheet on this page. The 10-mark scheme and all answers are in the answer key above. Re-check every answer and the marking scheme before publication.
16–19. Remediation, enrichment, homework, teacher reflection
Remediation. Use a bar model for each step. Enrichment. Invite learners to find or create three more examples at home or in the classroom and explain them. Homework. See above.
Teacher reflection. After teaching, record: which concepts learners understood; which misconceptions occurred; which activities worked; which learners need more practice; and what to improve next time.
Sources and standards
Alignment is pending verification and no external endorsement is claimed. Reference starting points named in the Courseversity standard: Common Core State Standards for Mathematics, Cambridge Primary and the IB Primary Years Programme. Specific standard codes will be added once checked against the official documents.