Εικόνες σελίδας
PDF

SECTION XII. Parts of one are called fractions. Fractions may be expressed by figures, as well as whole numbers. It requires two numbers to express a fraction; one to show into how many parts one is divided, and the other to show how many of those parts are used. For example, if we wish to express one half, (which means that one is divided into two equal parts, and that one part is used, we must use the figure 2 to express that one is divided into two equal parts and the figure 1 to show that one part is used. And these must be written in such a manner that we may always know what each of them is intended to express.

One half is usually written thus, £; one number above a line, and the other below it. The number below the line shows into how many parts one is divided, and the number above the line shows how many parts are used.

One third is written
Two thirds -
One fourth - -
Three fourths -

Two fifths - i Example of an apple signifies that the apple is

to be cut into 7 equal parts, and that 3 parts are to be used.

Let us apply an example to Plate II. refers to a square divided into 8 parts, and signifies that 5 parts are to be used.

We may observe, that, when one is divided into 3 parts, the parts are called thirds; when one is divided into 4 parts, the parts are called fourths, &c. that is, the fraction takes its name from the number of parts into which one is divided. The number

tul

under the line is called the denominator, because it gives name to the fraction; and the number above the line is called the numerator, because it shows the number of parts used. Thus , 10 is the denominator and 3 the numerator. · N. B. The pupil must be made familiar with this mode of expressing fractions, and must be able to apply it to any familiar objects, as apples, oranges, &c., and to the table, before he is allowed to proceed any farther. Particular care must be taken to make him understand what the denominator signifies, and what the numerator, as explained above. The denominator should always be explained first.

The following examples are a recapitulation of some of the foregoing sections, for the purpose of showing the application of the above method of writing fractions.

See Section VIII. A.. A. 1. In 2 how many times ]? Ans. *.* 2. In 3 how many times ?? Ans. . . 3. In 2 how many times ? Ans. 4. In 4 how many times ? 5. In 6 how many times ? 6. In 7 how many times ? 7. In 8 how many times ? 8. In 21how many times ? 9. In 31 how many times ? 10. Reduce 44 to an improper fraction. I 11. Reduce 34 to an improper fraction. 12. Reduce 5% to an improper fraction.

* When the numerator is larger than the denominator, the fraction is called an improper fraction. + 24 is read two and 1 half. It is called a mixed raumber.

That is, to find how many fifths there are in four and 1 fifth.

13. Reduce 67 to an improper fraction. 14. Reduce 8to an improper fraction. 15. Reduce 94 to an improper fraction.

[merged small][merged small][merged small][merged small][ocr errors][ocr errors][merged small][ocr errors][ocr errors]
[merged small][merged small][merged small][ocr errors][merged small][merged small][graphic][merged small]
[ocr errors]

* 4. 12 is of what number? 5. 15 is of what number?

is of what number? 7. 20 is of what number? 8. 24 is of what number? 9. 28 is of what number? 10. 30 is so of what number?

3 is of what number? 12. 4 is of what number?

5 is of what number?

8 is of what number? 15. 9 is of what number?

is of what number? 17. 25 is 4 of what number?

is of what number? 19. 43 is 9 of what number? 20. 54 is of what number?

Miscellaneous Examples. 1. A man sold 8 yards of cloth for 3 dollars a yard; what did it come to ?

2. A man sold a horse for 76 dollars, which was of what it cost him; how much did it cost him?

3. A man sold of a gallon of wine for 40 cents; what was that a gallon ?

4. If it will take 1% yards of cloth to make a coat, how many yards will it take to make 7 coats ?

5. If i horse consume 37 bushels of oats in 2 days, how much would 2 horses in 5 days ?

6. If, when the days are 94 hours long, a man perform a journey in 10 days, in how many days would he perform it when the days are 12 hours long?

7. A man sold 8 yards of cloth for 7 dollars a yard, and received & firkins of butter at 6dollars, a firkin; how much was then due to him?

8. Two men are 33 miles apart, and are travel

« ΠροηγούμενηΣυνέχεια »