DuckMath

Addition and Subtraction Games: Build Fast Mental Math

By the Duck Math team ·

Illustration for Addition and Subtraction Games: Build Fast Mental Math

Children who are fluent with addition and subtraction find every later topic easier. Fluency comes from strategies like making a ten and counting on, practised in short rounds.

Strategies to teach first

05101520+6
15 − 9 as the gap between 9 and 15: a jump of 6.
  • Counting on: for 8 + 3, start at 8 and count 9, 10, 11.
  • Making ten: 8 + 5 = 8 + 2 + 3 = 13.
  • Doubles and near doubles: 6 + 7 is 6 + 6 + 1.
  • Subtraction as the gap: 15 − 9 is how far from 9 up to 15, which is 6.

Games that practise them

  • Quick Sum Sprint: 60-second rounds with an Easy level within 20.
  • Math Duck: early levels have missing-number sums within 12.
  • Duck Math Dash: the first five gates use sums within 20.

Keep errors useful

After a wrong answer, say the full equation aloud once: "15 minus 9 is 6". The game shows the correct equation to make this easy.

Questions

How fast should a child be at addition within 20?

Many teachers aim for quick recall within a few seconds by the end of grade 2, but expectations vary by school.

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