PracticeQuestionsYears 1–7
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Adding and subtracting: mental and column methods

Year 3 · Lower Key Stage 2 · 3NF-1, 3NF-3, 3AS-1 to 3AS-3 — Facts that bridge 10; scale facts by 10; complements to 100; columns

Draft — awaiting teacher review

Builds on: Adding and subtracting within 100 (Year 2), Hundreds, tens and ones (Year 3)

I

Concept Anchor

In column subtraction, start with the ones. If the top digit is smaller, exchange 1 ten for 10 ones.

Worked example

352−127352 - 127

  1. 1.Ones: 2 − 7 cannot be done. Exchange: 5 tens become 4 tens, 2 ones become 12.
  2. 2.12 − 7 = 5.
  3. 3.Tens: 4 − 2 = 2.
  4. 4.Hundreds: 3 − 1 = 2. Answer: 225.
II

Guided Check

What must be added to 47 to make 100?

    III

    Independent Diagnostic Practice

    Q1Year 33NF-3 — Scale a fact by 10·Fluency·●○○Draft — awaiting teacher review

    7+8=157 + 8 = 15. So what is 70+8070 + 80?

    Q2Year 33AS-1 — Complements to 100·Reasoning·●●○Draft — awaiting teacher review

    What must be added to 64 to make 100?

    Q3Year 33AS-2 — Column subtraction with exchange·Problem Solving·●●●Draft — awaiting teacher review

    Use columns to work out 352−127352 - 127.