Ray's New Practical Arithmetic · Arts. 119–121 · Unit 10: Fractions
59. Dividing fractions
Goal: Your child divides by a fraction by inverting the divisor, finds what part one number is of another, and simplifies complex fractions.
You'll need
- The book
- A slate, small whiteboard or scrap paper
- A notebook and pencil
What's in the book
Division of fractions with worked examples about ribbon and apples, the rule (invert the divisor and multiply), problems, finding what part one number is of another, and complex fractions with miscellaneous examples.
The lesson, step by step
Warm-up
Mental: How many halves in 3? (6.) How many quarters in 2? (8.)
The idea
Read:
Division of Fractions is the process of finding the quotient of two fractional numbers.
Work a book-style example: if 3 yards cost 3/4 of a dollar, 1 yard costs 3/4 ÷ 3 = 1/4 of a dollar.
The rule
Read:
Multiply the dividend by the divisor with its terms inverted.
Example: 3/4 ÷ 1/8 = 3/4 × 8/1 = 6. Ask: How many eighths fit in three-fourths? (6.)
What part
Read:
What part one number is of another is found by division.
Together:
1 is what part of 2?
2 is what part of 3?
(1/2 and 2/3.)
Complex fractions
Read:
Complex fractions, (Art. 100) are reduced to simple fractions by division.
Show one: (1/2) over (3/4) = 1/2 ÷ 3/4 = 2/3.
Independent practice
Your child does problems 6 to 12 (word problems), some of the drill problems, and the "what part" problems.
Check and wrap-up
Answers are printed for the word and miscellaneous problems. Mental: 2 ÷ 1/3? (6.) 1/2 ÷ 2? (1/4.)
Answers to the book's problems
What part: 3 is 3/4 of 4.
Worked out for this site from the scan. If a number in your copy differs, trust the book.