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THE NEW  STUDENT'S   REFERENCE  WORK

2179

DIVISION OF FRACTIONS.

1. To divide a fraction by an integer. In multiplications of fractions we learned that a fraction was multiplied by multiplying the numerator or dividing the denominator. In division of fractions the reverse is true. A fraction is divided by dividing the numerator or multiplying the denominator.

Divide % by 3 %-j-3 = %

Divide % by 2

1 i	1     1 i

i

Divide the following, using the method best adapted to the example:


 * -4

f-5

- — 7 — 4

31 — 8

tt-7 5

20f


 * t-12 6|-10 — 15

2. To divide an integer or a fraction by a fraction: Divide 4 by f. We may think of f as | of 2. Divide 4 by | of 2. 4 divided by 2 is the same as finding \ of 4, but as we were to divide by only \ of 2, our result is only J of what it should be, so we multiply by 3.

2

Thus we see that 4 ~- \ is the same as       =s 6.

We have inverted our divisor and multiplied. This is the method to be used, invert the divisor and proceed as in multiplication.

Examples in division:

f-l l-f

74-

1-51

If

I 7f

18f 12$.

24} —

3

4

-7ft

124

8 ft

-31

(REVIEW) EXERCISE 22.

Find the G. G. F. of:

1.   21,    35,   49

2.   63,    84,    105

3.   48,   60,   96,   108

4.   75,    150,   225,   250

5.   12,   18,   42,   48.

Find the L. C. M. of:

6.   14,   21,    54,    56,   84

7.   3,   15,   12,   42,   60

8.   12,    20,    30,    45

9.   5,   12,    18,   30,   60 10.   24,   36,   52,   48,   72.