Ray's New Primary Arithmetic · Lesson XLVIII · Unit 5: Multiplication

48. Multiplying by 10

Goal: Your child knows the 10 times table by heart, both ways round, and uses it in story problems.

⏱ About 15 minutes · 7 steps

Open it at the Internet Archive ↗

You'll need

  • About 20 small counters: dried beans, buttons, pennies or pebbles (the book suggests marbles, beans or pebbles)
  • A slate, small whiteboard or paper and pencil

What's in the book

The table from "1 times 10 is 10" to "10 times 10 are 100", with each fact also turned around, then about nine story problems on prices and quantities. The first has a worked solution.

The lesson, step by step

  1. Warm up

    Count by 10s as far as your child can go. Then ask three facts from the earlier tables.

  2. Build a few facts

    Make 3 groups of 10 beans: "3 times 10 are 30." Then 4 groups, then 5.

  3. Both ways round

    Show that 3 times 10 and 10 times 3 give the same total: turn the rows of beans sideways.

  4. Read the table

    Read the table on the book page together, then alone.

  5. Cover and recall

    Cover the answers and ask the facts out of order.

  6. Story problems

    Read the problems aloud. They go like this:

    I bought 10 pencils, at 2 cents each: how much did they cost?

    If 10 marbles are given for 1 cent, how many must be given for 7 cents?

    Your child answers in a full sentence, as the worked solution does: "The melons cost 2 times 8 cents, which are 16 cents."

  7. Wrap up

    Your child writes the table from memory, as far as they can.

Afterwards

Say the table aloud each day, then answer five facts out of order. Move on when it comes instantly.

Tip

Times 10 puts a naught on the end.

Answers to the book's problems

1. 20 cents. 2. 30 dollars. 3. 40 pecks. 4. 50 pounds. 5. 60 dollars. 6. 70 marbles. 7. 80 cents. 8. 90 dollars. 9. 100 dollars.

Worked out for this site from the scan. If a number in your copy differs, trust the book.

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