AC9M3A02 • Year 3 Maths

Efficient Mental Addition and Subtraction (AC9M3A02)

extend and apply knowledge of addition and subtraction facts to 20 to develop efficient mental strategies for computation with larger numbers without a calculator

Choose a learning activity. Practice and Test use short shuffled attempts. Repeat quiz practice to access more of the full question bank.

Unit focus

  • Known facts such as doubles, complements to 10 and fact families can be extended to tens and hundreds for efficient mental calculation.
  • Use this routine: Recall known fact → Adjust place value → Choose strategy → Calculate mentally → Check.
  • Watch for counting by ones: Use a known fact or place-value relationship.
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