Ray's New Practical Arithmetic · Art. 80 · Unit 8: Operations with Compound Numbers

45. Dividing compound numbers

Goal: Your child divides a measure into equal parts, starting from the largest unit and changing each remainder into the next smaller unit.

⏱ About 35 minutes · 7 steps

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You'll need

  • The book
  • A slate, small whiteboard or scrap paper
  • A notebook and pencil

What's in the book

Division of compound numbers: two cases (how often one measure is contained in another, and dividing into equal parts), a worked example, the rule, and problems 4 to 19 with printed answers.

The lesson, step by step

  1. Warm-up

    Mental: 1 bushel ÷ 2? (2 pk.) 1 hour ÷ 4? (15 min.) 1 lb. ÷ 8? (2 oz.)

  2. Two cases

    Read:

    To find how often one Compound Number is contained in another Compound Number.

    To divide a Compound Number into a given number of equal parts. This is properly Compound Division.

    SayFor the first, change both to the same unit and divide. The second is today's main work.

  3. Work the book example

    Read:

    Divide 14 bu. 2 pk. 1 qt. by 3.

    14 bu. ÷ 3 = 4 bu., 2 bu. left. 2 bu. = 8 pk., + 2 = 10 pk.; ÷ 3 = 3 pk., 1 pk. left. 1 pk. = 8 qt., + 1 = 9 qt.; ÷ 3 = 3 qt. Answer 4 bu. 3 pk. 3 qt.

  4. The rule

    Read:

    Begin with the highest denomination, divide each number separately, and write the quotient beneath.

    If a remainder occurs after any division, reduce it to the next lower denomination

  5. Guided practice

    Together:

    I traveled 39 mi. 288 rd. in 7 hr.: at what rate per hour did I travel?

    (5 mi. 224 rd.)

  6. Independent practice

    Your child does problems 4 to 15, such as:

    Eleven casks of sugar weigh 35 cwt. 44 lb. 12 oz.: what is the average weight of each?

  7. Check and wrap-up

    Answers are printed; prove one by multiplying back. Mental: 3 hr. ÷ 4? (45 min.)

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