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.
