Lesson

Ratio word problems

Primary EducationGrade 6MathematicsCV-PRI-G06-MATH-NUM-U02-L0735–45 min

You will learn

  • Share in a ratio.
  • Find parts from a total.
  • Find the total from a part.
  • Check the answer.

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

share
Divide into parts.
part
One share.
total
All together.
ratio
Comparison.

1. Discover: sharing money

Two friends share 40 in the ratio 3 : 5. How much does each get?

2. Understand: ratio problems

  • Total parts: 3 + 5 = 8. One part: 40 ÷ 8 = 5.
  • First friend: 3 × 5 = 15. Second: 5 × 5 = 25.
  • Check: 15 + 25 = 40.
  • Paint 2 : 3 in 20 litres: 20 ÷ 5 = 4, so 8 and 12 litres.
Remember: Total parts, one part, then each share.

3. Explore: share

You need paper.

  1. Add the parts.
  2. Divide the total.
  3. Multiply for each.
  4. Add to check.
Think about it: what did you notice?

15 and 25.

4. Practise

Guided practice

Question 1. Total parts?

8.

Question 2. One part?

5.

Question 3. Larger share?

25.

Independent practice

  1. Share 40 in 3 : 5, smaller share
  2. Share 20 L in 2 : 3, larger
  3. Share 24 in 1 : 2
  4. Share 30 in 2 : 3
  5. Total if 3 parts = 12 (3 : 5)

Answers are in the answer key below. Try first, then check.

5. Apply: everyday mathematics

Share 40 in the ratio 3 : 5. Larger share?

Show a sample answer

25.

6. Common mistake

Mistake: Dividing the total by one term.
Fix: Divide by the sum of the terms.

7. Check and master

Answer all questions. You will see feedback after each one.

1. 40 in 3 : 5, smaller share:

2. 20 L in 2 : 3, larger:

3. 24 in 1 : 2, larger:

4. 30 in 2 : 3, smaller:

5. 3 parts = 12 in 3 : 5, total:

Challenge. Share 40 in 3 : 5, larger share:

Your result appears here after you answer every question.

8. Key takeaways

  • Add the parts.
  • Find one part.
  • Check the sum.

9. Next lesson

Next lesson: Real-world applications. Keep going with the next idea in this course.

Printable worksheet

  1. 40 in 3:5, smaller
  2. 20 L in 2:3, larger
  3. 24 in 1:2, larger
  4. 30 in 2:3, smaller
  5. 3 parts = 12 (3:5), total

Homework

Share 60 in the ratio 1 : 4.

Answer key and marking scheme

Question Expected response Marks
40 in 3:5, smaller 15 2
20 L in 2:3, larger 12 2
24 in 1:2, larger 16 2
30 in 2:3, smaller 12 2
3 parts = 12 (3:5), total 32 2
Total 10

Practice answers: Worksheet: 1 15; 2 12; 3 16; 4 12; 5 32.

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 Share in a ratio 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 Find parts from a total 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 Find the total from a part 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 Check the answer 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

  1. Find the misconception: Dividing the total by one term. Divide by the sum of the terms.
  2. Explain another way: use real objects first, then pictures.
  3. Show a simpler example: Equal sharing.
  4. Guided practice: work through one example together and let the learner try the next one.
  5. Reassess: use the quiz again or the worksheet.
  6. Move on when the learner shows Silver-level evidence independently.

Teacher package

1–5. Objectives, prerequisites, materials, preparation, duration

Lesson objectives. Learners will: share in a ratio; find parts from a total; find the total from a part; check the answer.

Prerequisite knowledge. Lessons 2 and 3.

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. 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. Dividing the total by one term. Divide by the sum of the terms.

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. Equal sharing. 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.

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