Ray's New Intellectual Arithmetic · Lesson XIV · Unit 2: Multiplying and dividing

14. Multiplying in stories

Goal: Your child uses multiplication in stories about prices, distances, rows and work.

⏱ About 20 minutes · 5 steps

Open it at the Internet Archive ↗

You'll need

  • The book page (press “📖 Book page”, or use a printed copy)
  • Paper for jotting, though the work is meant to be done in the head

What's in the book

Twenty-five problems with several model solutions, such as “7 oranges will cost 7 times 2 cents, which are 14 cents”, and a note that $6 is read “6 dollars”.

The lesson, step by step

  1. Warm up

    Ask three or four problems from the last lesson again, out of order. Your child answers and says why.

  2. Show the reasoning

    SayA man travels 7 miles an hour. In 8 hours he travels 8 times 7 miles, which are 56 miles.

    Look out for the one problem that goes the other way: if 2 men take 3 days, 1 man takes 2 times 3 days, which are 6 days.

  3. Work the problems aloud

    Read each problem on the page aloud. Your child answers, then explains in a full sentence, the way the book's model solutions do. The problems go like this:

    On a chess-board are 8 rows of squares, and 8 squares in each row: how many squares?

    If 2 men can do a piece of work in 3 days, in how many days can 1 man do it?

    An orchard has 11 rows of trees with 7 trees in each row: how many trees?

  4. Ask “Why?”

    After each answer ask “Why?” or “How do you know?” Ray's wants the reasoning said aloud, not just the number. If your child stalls, go back to the model and say the first half of the explanation together.

  5. Wrap up

    Pick the two problems that were hardest today. Tomorrow, start with those as the warm-up.

Afterwards

Do the rest of the lesson's problems over the next day or two, a few at a time. Move on when your child can explain them without help.

Answers to the book's problems

1) 14 cents. 2) 21. 3) 30. 4) 56. 5) $48. 6) $27. 7) $28. 8) 80 cents. 9) $42. 10) $40. 11) 56 mi. 12) 64. 13) 77. 14) $54. 15) 72 cents. 16) 96 cents. 17) 18 mi. 18) 6 days. 19) 12. 20) 24. 21) 32 days. 22) $48. 23) 63 men. 24) 88 persons. 25) $56.

Worked out for this site from the scan. If a number in your copy differs, trust the book. Every answer is in Ray's own Key ↗.

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