Divide anything, as the line A B, into two equal parts; Divide the line A. B. into three equal parts; each part is one third of the line A B. 231. Equal parts of anything are fractions of that thing. As halves of a dollar, twelfths of a foot, etc. 232. One half is expressed in figures thus: or 1⁄2; one third thus, or 3; two thirds, thus, or 23. 233. The figure written under the short line, as in or 3⁄4, has been divided. A figure thus written is the denom- 234. The figure written above the line, as in or 2/3, shows how many of the fractional parts, such as halves, thirds, etc., compose the fraction. A figure thus writ ten is the numerator of the fraction. Thus, means two of the three equal parts of the same unit. REDUCTION OF FRACTIONS. CASE I. 235. To reduce an integer or a mixed number to an improper 16 G to 10 To to to to to to to to to to to to to to H 1 1. If the line A B be divided into two equal parts, what is each part called? If a line is divided into four equal parts, what is each part called? If into eight? If into sixteen ? 2. If a unit be divided into three equal parts, what is 3. How many halves in the line A B? 7ths ? 5. How many halves in one apple? How many halves in two apples? In three? In four? In five ? 6. How many thirds in two units? How many fourths, in two units? How many eighths in two units? In three units ? Such fractions as,,, etc., are called improper fractions. 7. How may you find the number of eighths in any number? This process is called reducing an integer to an improper fraction. 8. State a general rule for reducing an integer to an improper fraction. 9. Reduce 4 to 4ths; to 5ths; to 6ths; to 7ths. 10. Change 8 to 3rds; 9 to 8ths; 12 to 10ths. 11. How many 5ths in 2? In 2? In 23? In 2? Numbers composed of an integer and a fraction are called mixed numbers. 12. State a general rule for changing a mixed number to an improper fraction. 13. Reduce 83 to 3rds; 73 to 4ths; 5% to 9ths. 14. Reduce 6 to 12ths; 9 to 10ths; 12 to 7ths. 15. Change 3 to 5ths; 5% to 6ths; 4 to 8ths. Reduce to improper fractions: 236. To reduce an improper fraction to an integer or to a mixed number. 1. How many 5ths in 1 ? How many units in ? In 15? In 20? In 25. 4. State a general rule for changing an improper fraction to an integer or to a mixed number. 5. When is the result an integer? When is the result a 237. To change a fraction to higher or lower terms. 1. How many 4ths in 1 ? 2. How many 8ths in 1 ? In ? In ? In ? 3. How many 16ths in 1 ? In? In? In ? 4. Which has the greater value, or ? 5. Is there any difference in the value of and? Is there a difference in their form? 6. How may be changed to ? How may be changed to? is said to be in lower terms than, because the denom- A fraction may be considered as an indicated division. 7. In the fraction 25, which term is the dividend? Which by 5; what is the quotient? Does 25 or 5? What general principle is here illustrated? 10. Change to lower terms. Reduce to lower terms. 11. State a general rule for reducing a fraction to lower terms. 8 13. Reduce to 5ths; 4 to 8ths; to 3rds. 14. How do you know what divisor to use in order to change 35ths to 5ths ? 15. State a general rule for examples such as example 13. 16. Reduce to 12ths; to 9ths; 72 25 to 15ths. to 9ths; to 24ths; to 5ths. 18. Change to 10ths; to 18ths; to 24ths; to 50ths. This 17. Change is reducing a fraction to higher terms. Upon what 19. State a general rule for reducing fractions to higher terms. 20. Reduce to 15ths; to 20ths; to 40ths; to 60ths. 21. Reduce to 27ths; to 56ths; 22. Reduce to 10ths. First reduce to 5ths. to 48ths. 23. Reduce 2 to 15ths; to 20ths; to 16ths. CASE I V. 238. To reduce a fraction to lowest terms. A fraction is in lowest terms when its numerator and de nominator are prime to each other. 1. Reduce to lowest terms. SOLUTION. Divide each term by 3: 12÷3 4. 27÷3 9 SUGGESTION. Divide each term by 12, the greatest common factor of of the two terms. |