Ray's New Practical Arithmetic · Arts. 54–55 · Unit 6: United States Money

27. Changing dollars, cents and mills

Goal: Your child changes dollars to cents or mills and back, by annexing ciphers or placing the decimal point.

⏱ About 35 minutes · 6 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

Rules for reducing United States money from one denomination to another, the decimal-point short cut, and 19 problems with answers.

The lesson, step by step

  1. Warm-up

    Mental: 3 dollars is how many cents? 250 cents is how many dollars? 5 cents is how many mills?

  2. Down to smaller units

    Read:

    Multiply the number of cents by ten; that is, annex one cipher.

    Multiply the number of dollars by one hundred; that is, annex two ciphers.

    SaySmaller units mean more of them, so we multiply.

  3. Up to larger units

    Read:

    Divide the number of cents by one hundred; that is, cut off two figures from the right.

    And the short cut:

    Put the decimal point between the second and third figures from the right.

  4. Guided practice

    Do the first two together:

    1. Reduce 17 ct. to mills.

    2. Reduce 28 ct. to mills.

    (Answers 170 m. and 280 m.)

  5. Independent practice

    Your child does the rest of the 19 problems.

  6. Check and wrap-up

    Answers are printed. Mental finish: 4000 mills is how many dollars? (4.) $1.25 is how many cents? (125.)

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