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Addition and subtraction within 20

Mathematics · Addition & Subtraction · procedural

Add and subtract within 20 using strategies such as making ten, decomposing a number leading to ten, and using known facts

What mastery looks like

  • Solve 8 + 6 using making ten: 8 + 2 + 4 = 14
  • Solve 13 − 4 by decomposing: 13 − 3 − 1 = 9
  • Use a known fact (8 + 4 = 12) to derive 12 − 8 = 4

Check your understanding

If Addition and subtraction within 20 needs to work out '8 + 6', can they split the 6 into 2 + 4, use the 2 to fill up to 10, then add the remaining 4 to get 14?