Ray's New Primary Arithmetic · Lesson LXI · Unit 6: Division

61. Dividing by 10

Goal: Your child knows how many times 10 is contained in each number up to 100, 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 "10 in 10, 1 time" to "10 in 100, 10 times", with the matching facts the other way round, then story problems on buying, sharing and measures. The first has a worked solution.

The lesson, step by step

  1. Warm up

    Ask five facts from the 10 times table. Division is the times table backwards.

  2. Build it with counters

    Put out 30 beans. Ask: How many groups of 10 can you make? Make them and count the groups.

    Say it the book's way: "10 in 30, 3 times."

  3. Link to multiplying

    Ask: 3 times 10 are how many? So 10 is contained in 30 three times.

  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:

    How many melons, at 10 cents each, can you buy for 20 cents?

    If a quince is worth 10 apples, how many quinces can you get for 30 apples?

    The book's answers sound like this: "You can buy as many as 10 cents are contained times in ..."

  7. Wrap up

    Your child writes three division facts and the times-table fact that goes with each.

Afterwards

Mix this table into the daily warm-up with the 10 times table.

Answers to the book's problems

1. 2 melons. 2. 3 quinces. 3. 10 pears. 4. 5 oranges. 5. 6 dozen. 6. 7 coats. 7. 10 kites. 8. 9 balls. 9. 10 dimes.

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

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