Lesson

Comparing data

Primary EducationGrade 3MathematicsCV-PRI-G03-MATH-DAT-U01-L0645–60 min

You will learn

  • Compare two sets of numbers.
  • Find which set is bigger.
  • Find the difference between two totals.
  • Explain a comparison in a sentence.

Version 0.2 · expanded edition · expert review pending Standards alignment: pending verification. Written in the style of common primary school assessments. No exam result is promised.

Student lesson

The lesson in 60 seconds

  1. Compare two sets of numbers.
  2. Find which set is bigger.
  3. Subtract to find the difference.
  4. Say the comparison in a sentence.

Words to know

compare
Say how things are alike and different.
set
A group of data.
difference
How much more or less.
greater
Bigger.

1. Discover: two classes

Class 3A read 40 books and class 3B read 35. Which class read more? By how many?

2. Understand: comparing data

To compare two sets of data, find each total and then the difference.

  • 3A: 40 books. 3B: 35 books. 3A is greater. 40 − 35 = 5 more.
  • Shop A sold 30 loaves on Monday and shop B sold 45. 45 − 30 = 15 more at shop B.

Write a full sentence: “Shop B sold 15 more loaves than shop A.”

3A403B35
3A read 40; 3B read 35

Idea 1: Difference

50 and 38 differ by 50 − 38 = 12. 42 and 42 differ by 0.

Idea 2: Which is greater

Shop A sold 25 and shop B sold 60. Shop B sold more, by 60 − 25 = 35.

Idea 3: Totals

Class A has 18 and class B has 22. Together there are 40.

Why a sentence? A sentence tells what the numbers mean.

Remember: Find each total, then subtract to compare.

3. Worked examples

Example 1 (I show you): Difference

50 and 38.

  1. 50 − 38.

Answer: 12

Example 2 (We do it together): More

Shop A 25, shop B 60. How many more at B?

  1. 60 − 25.

Answer: 35

Example 3 (You try): Total

Class A 18, class B 22.

Show the steps and answer
  1. 18 + 22.

Answer: 40

Did you know?

The difference of two equal numbers is zero.

Why this matters

Comparing data helps us make fair choices.

4. Explore: compare two groups

You need two small tables of numbers.

  1. Write the total for each class.
  2. Say which is greater.
  3. Subtract to find the difference.
  4. Write a full sentence.
Think about it: what did you notice?

The sentence names who has more and by how many.

5. Practise

Say it in a sentence

Use these starters when you talk about the lesson. Say them out loud.

  • ___ is greater than ___.
  • The difference is ___.
  • Together there are ___.
  • ___ has ___ more than ___.

Guided practice

Question 1. 3A 40, 3B 35. Which is greater?

3A.

Question 2. By how many?

5.

Question 3. Shop A 30, shop B 45. Difference?

15.

Independent practice

Level 1: Start

  1. 50 and 38: difference
  2. 42 and 42: difference
  3. Which is greater: 67 or 76?
  4. Shop A 25, shop B 60: how many more at B?
  5. Class A 18, class B 22: total

Level 2: Grow

  1. 80 and 65: difference
  2. Which is greater: 91 or 19?
  3. Shop A 40, shop B 75: how many more at B?

Level 3: Stretch

  1. 120 and 85: difference
  2. Class A 36 and class B 29 together
  3. Ben says 56 and 48 differ by 104. What is wrong?

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

6. Apply: everyday mathematics

Team X scored 56 points and team Y scored 48. How many more did X score?

Show a sample answer

8 more.

Another one. Write a sentence comparing class A with 28 pupils and class B with 34 pupils.

Show a sample answer

Class B has 6 more pupils than class A.

7. Common mistakes

Mistake: Adding instead of subtracting to compare.
Fix: Subtract to find the difference.
Another mistake: Adding to find the difference.
Fix: Subtract to find the difference.
Another mistake: Comparing different things.
Fix: Compare the same kind of data.

8. Lesson summary and revision card

I can…

  • I can compare two sets of numbers.
  • I can find which set is bigger.
  • I can find the difference.
  • I can explain a comparison in a sentence.

9. Check and master

Answer all 14 questions. You will see feedback after each one.

1. 3A read 40 and 3B read 35. The difference is…

2. Shop A 30, shop B 45. Which sold more?

3. 50 and 38 differ by…

4. 42 and 42 differ by…

5. Class A 18 and class B 22 together:

6. Class A 45 and class B 38. The difference is…

7. Shop A sold 70 and shop B sold 55. Which sold more?

8. 60 and 48 differ by…

9. 25 and 25 differ by…

10. Team X scored 64 and team Y scored 59. X scored how many more?

11. Class A has 33 and class B has 27. Together there are…

12. To compare two sets of numbers we can find the…

Challenge 1. Team X scored 56 and team Y scored 48. X scored how many more?

Challenge 2. Class A has 45 and class B has 38. Then 10 more pupils join class B. Which class is bigger now and by how many?

Your result appears here after you answer every question.

10. Key takeaways

  • Compare totals.
  • Subtract to find the difference.
  • Write a sentence.

11. Next lesson

Next lesson: Drawing conclusions. Keep going with the next idea in this course.

Exam practice

These questions are written in the style of common school and international primary assessments. Try them on your own, without looking back. Then check your answers in the marking guide. The marks are shown in brackets.

  1. Find the difference between 50 and 38. [2 marks]
  2. Shop A sold 25 and shop B sold 60. How many more did B sell? [2 marks]
  3. Class A has 18 and class B has 22. How many together? [2 marks]
  4. Which is greater: 67 or 76? [1 mark]
  5. Ana says the difference between 42 and 42 is 84. Is she right? Explain. [3 marks]

Total: 10 marks.

Marking guide and model answers
  1. 50 − 38 [1] = 12 [1]
  2. 60 − 25 [1] = 35 [1]
  3. 18 + 22 [1] = 40 [1]
  4. 76 [1]
  5. No [1]. They are equal [1]. The difference is 0 [1].

Score guide: 9 to 10 = secure. 6 to 8 = nearly there, revise the parts you missed. Under 6 = work through the lesson again with a grown-up.

Printable worksheet

  1. 50 and 38: difference
  2. 42 and 42: difference
  3. Greater: 67 or 76
  4. Shop A 25, shop B 60: how many more at B
  5. Class A 18 and class B 22: total
  6. 50 and 38 differ by ___.
  7. 42 and 42 differ by ___.
  8. Class A 18 and class B 22 together: ___
  9. Team X 56, team Y 48: X scored ___ more.
  10. Shop A 30, shop B 45. Which sold more?

Homework

Compare the number of pupils in two classes you know. Write a sentence.

Answer key and marking scheme

Question Expected response Marks
50 and 38: difference 12 2
42 and 42: difference 0 2
Greater: 67 or 76 76 2
Shop A 25, shop B 60: how many more at B 35 2
Class A 18 and class B 22: total 40 2
Total 10

Practice answers: Worksheet: 1 12; 2 0; 3 76; 4 35; 5 40.

Quiz answers: 1 A, 2 B, 3 C, 4 A, 5 B, 6 A, 7 B, 8 C, 9 A, 10 B, 11 C, 12 A, Challenge 1 C, Challenge 2 C.

Extra worksheet answers (items 6 onward): 6 12; 7 0; 8 40; 9 8; 10 shop B.

Independent practice answers. Level 1: 1 12; 2 0; 3 76; 4 35 more; 5 40. Level 2: 1 15; 2 91; 3 35. Level 3: 1 35; 2 65; 3 He added. The difference is 56 − 48 = 8..

Mastery and remediation

Objective Bronze (Developing) Silver (Proficient) Gold (Advanced)
O1 Compare two sets of numbers 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 which set is bigger 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 difference between two totals 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 Explain a comparison in a sentence 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 8 of 12 core questions correct; Silver = all 12; Gold = all 12 plus both challenge questions. A badge is never a full record of progress.

If a learner struggles

  1. Find the misconception: Adding instead of subtracting to compare. Subtract to find the difference.
  2. Explain another way: use real objects first, then pictures.
  3. Show a simpler example: Practise 2-digit subtraction with number lines.
  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.

For parents and guardians

In this lesson your child compares two sets of data and explains the difference. You do not need to be good at mathematics to help.

  • Compare scores or heights in your family.
  • Ask: who has more? by how much?
  • Use real numbers.
  • Ask “how do you know?” after each answer, and listen.
  • Praise effort, not only right answers. Mistakes are how we learn.
  • Ten to fifteen minutes a day is better than one long session.

Teacher package

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

Lesson objectives. Learners will: compare two sets of numbers; find which set is bigger; find the difference between two totals; explain a comparison in a sentence.

Prerequisite knowledge. Lessons 2 to 5.

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. 45–60 minutes. It can be split into two shorter sessions.

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 two small tables of numbers. 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.

Key questions. Which is greater? What is the difference? What is the total?

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. Adding instead of subtracting to compare. Subtract to find the difference.

13–15. Assessment questions, answer keys, marking scheme

Use the quiz and worksheet on this page. The 10-mark exam practice scheme, the 10-mark scheme and all answers are in the answer sections above. Re-check every answer and the marking scheme before publication.

16–19. Remediation, enrichment, homework, teacher reflection

Remediation. Practise 2-digit subtraction with number lines. 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.

Research used to shape this lesson. Common Core 3.MD.B.3 and 2.MD.D.10; Cambridge Primary Mathematics Stage 3 (comparing data). These sources informed the lesson; no official alignment is claimed.

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