Ray's New Practical Arithmetic · Arts. 122–127 · Unit 10: Fractions
60. Fractions with money and measures
Goal: Your child works with fractions of dollars and of measures: changing a fraction of one unit to another and finding what part one measure is of another.
You'll need
- The book
- A slate, small whiteboard or scrap paper
- A notebook and pencil
What's in the book
Fractional compound numbers: money problems with fractions of a cent, reducing a fraction to a lower or higher unit, finding the value of a fraction in whole units, finding what part one measure is of another, and a review of reduction.
The lesson, step by step
Warm-up
Mental: 1/2 of a dollar in cents? 3/4 of an hour in minutes? 1/4 of a yard in inches?
Money with fractions
Together:
Find the cost of 9 yd. of muslin, at 12½ ct. a yd.
9 × 12½ = 112½ cents = $1.12½.
Down to a smaller unit
Read:
A fraction is reduced to a lower denomination by multiplication (Art. 63, Rule I).
Read:
This is called finding the value of a fraction in integers.
Example: 2/5 of a day = 2/5 × 24 hr. = 9 3/5 hr. = 9 hr. 36 min.
Up to a larger unit
Read:
A fraction is reduced to a higher denomination by division (Art. 63, Rule II).
Example: 4 qt. is 4/32 = 1/8 of a bushel.
What part
Read:
To find what part one compound number is of another, reduce them to the same denomination and proceed as in Art. 120.
Together:
2 ft. 3 in. is what part of a yard?
27 in. out of 36 in. = 3/4.
Independent practice
Your child does some of each kind, including:
At 18¾ ct. per yard, how many yards of muslin can be purchased for $2.25?
What part of a day is 13 hr. 30 min.?
Check and wrap-up
Answers are printed for most problems; see below for the rest. Mental: what part of a foot is 8 inches? (2/3.)
Answers to the book's problems
Art. 126: 4 qt. = 1/8 bu.; 4 ft. = 8/33 rd. Art. 127: problem 2, 2 ft. 6 in. is 3/8 of 6 ft. 8 in.; problem 3, 2 pk. 4 qt. is 5/8 of a bushel.
Worked out for this site from the scan. If a number in your copy differs, trust the book.