Ray's New Primary Arithmetic · Lesson XXII · Unit 3: Addition

22. Adding three numbers

Goal: Your child adds three small numbers in their head.

⏱ About 15 minutes · 3 steps

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You'll need

  • About 20 small counters: dried beans, buttons, pennies or pebbles (the book suggests marbles, beans or pebbles)

What's in the book

Facts with three numbers, such as "How many are 4 and 5 and 7?" and "How many are 2 and 4 and 2?". The lesson takes two pages.

The lesson, step by step

  1. Show the method

    SayFor 4 and 5 and 7: 4 and 5 are 9; 9 and 7 are 16.

    Use counters in three groups the first time.

  2. Look for a ten

    For 3 and 6 and 7, notice that 3 and 7 make 10, so the answer is 16. Adding in a different order is allowed.

  3. Book questions

    Work through the questions on the pages, aloud.

Afterwards

Ask one three-number question at every meal for a week.

@teddyrookbook GitHub