Courseversity

Lesson

Subtraction within 1,000

Primary EducationGrade 2MathematicsCV-PRI-G02-MATH-OPS-U01-L0645–60 min

You will learn

  • Subtract hundreds, tens and ones.
  • Line up the places.
  • Subtract multiples of 100 and 10.
  • Check by adding.

Version 0.2 · expanded edition · built from cited public sources Content is based on the official frameworks and sources listed under Sources and standards. No official endorsement is claimed. Written in the style of common primary school assessments. No exam result is promised.

Student lesson

The lesson in 60 seconds

  1. Subtract hundreds, tens and ones.
  2. Line up the places.
  3. Subtract multiples of 100 and 10 mentally.
  4. Check by adding.

Words to know

subtract
Take away.
difference
What is left.
column
Digits lined up by place.
check
Make sure the answer is right.

1. Discover: unsold goods

A shop has 685 sweets and sells 243. How many sweets are left?

2. Understand: subtracting within 1,000

Line up the places and subtract each column: 685 − 243. Ones 5 − 3 = 2; tens 8 − 4 = 4; hundreds 6 − 2 = 4. The answer is 442.

Check by adding: 442 + 243 = 685.

Easy ones: 500 − 200 = 300 and 890 − 460 = 430.

Idea 1: By place

758 − 325: ones 8 − 5 = 3, tens 50 − 20 = 30, hundreds 700 − 300 = 400. The difference is 433.

Idea 2: Line up the places

Write ones under ones, tens under tens and hundreds under hundreds. Why? You can only subtract digits in the same place.

Idea 3: Multiples of 100 and 10

600 − 300 = 300 because 6 − 3 = 3 hundreds. 870 − 240 = 630 because 87 − 24 = 63 tens.

Remember: Subtract ones, tens, then hundreds. Check with addition.

3. Worked examples

Example 1 (I show you): By place

758 − 325 = ?

  1. Ones: 8 − 5 = 3.
  2. Tens: 50 − 20 = 30.
  3. Hundreds: 700 − 300 = 400.

Answer: 433

Example 2 (We do it together): Tens

870 − 240 = ?

  1. 87 tens − 24 tens = 63 tens.

Answer: 630

Example 3 (You try): Check

Check 758 − 325 = 433.

Show the steps and answer
  1. Add 433 + 325.

Answer: 758. It matches.

Did you know?

Subtraction is used by builders to find how much material is left.

Why this matters

Subtracting to 1,000 helps us with money, distances and school counts.

4. Explore: column subtraction

You need squared paper.

  1. Write 685 and 243 in columns.
  2. Subtract ones, then tens, then hundreds.
  3. Check by adding 442 + 243.
  4. Try 976 − 532.
Think about it: what did you notice?

685 − 243 = 442. 976 − 532 = 444.

5. Practise

Say it in a sentence

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

  • The ones give ___.
  • The tens give ___.
  • The hundreds give ___.
  • The difference is ___.

Guided practice

Question 1. 685 − 243?

442.

Question 2. 500 − 200?

300.

Question 3. 890 − 460?

430.

Independent practice

Level 1: Start

  1. 758 − 325
  2. 600 − 300
  3. 487 − 153
  4. 925 − 612
  5. 870 − 240

Level 2: Grow

  1. 746 − 312 = ___.
  2. 950 − 430 = ___.
  3. 800 − 300 = ___.

Level 3: Stretch

  1. A school has 865 pupils and 342 are girls. How many are boys?
  2. 999 − 111 = ___.
  3. Kofi writes 568 − 24 as 568 − 240 = 328. What is wrong?

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

6. Apply: everyday mathematics

A shop has 685 sweets and sells 243. How many are left?

Show a sample answer

442 sweets.

Another one. A tank has 975 litres. 530 litres are used. How many are left?

Show a sample answer

445

7. Common mistakes

Mistake: Subtracting the top digit from the bottom digit.
Fix: The first number is the whole; take the second away.
Another mistake: Not lining up the places.
Fix: Ones under ones, tens under tens.
Another mistake: Subtracting the top from the bottom.
Fix: Take the bottom number from the top.

8. Lesson summary and revision card

I can…

  • I can subtract hundreds, tens and ones.
  • I can line up the places.
  • I can subtract multiples of 100 and 10.
  • I can check by adding.

9. Check and master

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

1. 685 − 243 =

2. 976 − 532 =

3. 500 − 200 =

4. 748 − 125 =

5. 890 − 460 =

6. 758 − 325 =

7. 600 − 300 =

8. 487 − 153 =

9. 925 − 612 =

10. 870 − 240 =

11. 900 − 400 =

12. To check 758 − 325 = 433 we add 433 +

Challenge 1. 999 − 456 =

Challenge 2. 678 − 234 − 100 =

Your result appears here after you answer every question.

10. Key takeaways

  • Line up the places.
  • Subtract place by place.
  • Check by adding.

11. Next lesson

Next lesson: Regrouping in subtraction. 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. Work out 745 − 321. [1 mark]
  2. Work out 800 − 300. [1 mark]
  3. Work out 968 − 536. [2 marks]
  4. A shop has 640 books and sells 230. How many are left? [2 marks]
  5. Ben says 574 − 63 = 514. Is he right? Explain. [3 marks]

Total: 9 marks.

Marking guide and model answers
  1. 424 [1]
  2. 500 [1]
  3. 432 [2]. Give 1 mark for one error.
  4. 640 − 230 [1] = 410 [1]
  5. Check 514 + 63 = 577 [1]; not 574 [1]; he is wrong, the answer is 511 [1]

Score guide: 8 to 9 = secure. 6 to 7 = nearly there, revise the parts you missed. Under 6 = work through the lesson again with a grown-up.

Printable worksheet

  1. 758 − 325
  2. 600 − 300
  3. 487 − 153
  4. 925 − 612
  5. 870 − 240
  6. 685 − 243 = ___.
  7. 976 − 532 = ___.
  8. 500 − 200 = ___.
  9. 748 − 125 = ___.
  10. 999 − 456 = ___.

Homework

Find two three-digit prices. Work out the difference between them.

Answer key and marking scheme

Question Expected response Marks
758 − 325 433 2
600 − 300 300 2
487 − 153 334 2
925 − 612 313 2
870 − 240 630 2
Total 10

Practice answers: Worksheet: 1 433; 2 300; 3 334; 4 313; 5 630.

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): 6 442; 7 444; 8 300; 9 623; 10 543.

Independent practice answers. Level 1: 1 433; 2 300; 3 334; 4 313; 5 630. Level 2: 1 434; 2 520; 3 500. Level 3: 1 523; 2 888; 3 He did not line up the places. 568 − 24 = 544..

Mastery and remediation

Objective Bronze (Developing) Silver (Proficient) Gold (Advanced)
O1 Subtract hundreds, tens and ones 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 Line up the places 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 Subtract multiples of 100 and 10 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 by adding 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

Courseversity badge thresholds (overall quiz score): Gold = 90–100%; Silver = 80–89.9%; Bronze = 70–79.9%. A badge is never a full record of progress.

If a learner struggles

  1. Find the misconception: Subtracting the top digit from the bottom digit. The first number is the whole; take the second away.
  2. Explain another way: use real objects first, then pictures.
  3. Show a simpler example: Use place value squares and take away hundreds, then tens, then ones.
  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 subtracts three-digit numbers without regrouping. You do not need to be good at mathematics to help.

  • Subtract prices up to 1,000 together.
  • Check each answer by adding.
  • Ask: which places did you subtract first?
  • 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: subtract hundreds, tens and ones; line up the places; subtract multiples of 100 and 10; check by adding.

Prerequisite knowledge. Lesson 5; Unit 1.

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 squared 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.

Key questions. Are the places lined up? What do the hundreds give? Can you check by adding?

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. Subtracting the top digit from the bottom digit. The first number is the whole; take the second away.

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

Use the quiz and worksheet on this page. The 9-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. Use place value squares and take away hundreds, then tens, then ones. 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

This lesson is based on the sources below, and no official 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. Where a standard code is named, it points to the official framework.

Official standards for this topic area. Common Core State Standards for Mathematics (official site): Grade 2 » Operations & Algebraic Thinking; Grade 2 » Number & Operations in Base Ten. These pages list the standards that cover this topic area; read them alongside the lesson.

Research used to shape this lesson. Common Core 2.NBT.B.7 (subtract within 1000); Cambridge Primary Mathematics Stage 2. These sources informed the lesson.

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