Basic Facts - Subtraction

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Subtraction

  • Subtraction basic facts encompass the traditional facts up to 19 - 9
  • Subtraction is taking a (smaller) set away from another (larger) one.
  • Counting back is the fundamental idea of subtraction.
  • Subtraction is closely linked to the addition basic facts, but students find them harder to memorise.
The following principles apply to subtraction facts:
  • Subtracting 0 or 1 is very easy (see the purple and blue parts of Table 5).
  • Subtracting two single digit numbers is easy (see top half of Table 5).
  • Subtraction involving doubles is easy (see the green parts of Table 5).
  • Subtraction is not commutative (7 – 2 ≠ 2 – 7)
  • Subtraction may lead to negative numbers.
Table 6 Counting strategies and subtraction basic facts to19



Table 6
Table 6