FINDING RECIPROCAL OF A NUMBER

Example 1 :

State the reciprocal of:

a) 3/4     b) 2/7     c)  4     d)  -1/2     e)  -2

f)  5/8     g)  -5/2     h)  -1     i)  0

Solution :

a) Reciprocal of 3/4 is 4/3.

b) Reciprocal of 2/7 is 7/2.

c) Reciprocal of 4 is 1/4.

d) Reciprocal of -1/2 is -2/1 that is -2.

e) Reciprocal of -2 is -1/2

f) Reciprocal of 5/8 is 8/5.

g) Reciprocal of -5/2 is -2/5.

h) Reciprocal of -1 is -1.

i) Reciprocal of 0 is undefined.

Example 2 :

4/7 of a number is 84. Find the number.

Solution :

4/7 of a number = 84 ----(1)

By finding 7/4 of the number, we can find that number.

Multiplying (1) by 7/4 on both sides.

(7/4) x (4/7) of a number = (7/4) x 84

Number = 7 x 21 ==> 147

So, the required number is 147.

Example 3 :

Find the quotient of 1/3 and 3/4.

Solution :

Let a = 1/3 and b = 3/4

To find the quotient of a and b, we have to divide a by b.

= (1/3) / (3/4)

If two fractions are divided, keep the first fraction as it is and change the division sign as multiplication and write the reciprocal of the second fraction.

= (1/3) x (4/3)

= 4/9

Example 4 :

Find the reciprocal of 5 and 7/8.

Solution :

Product of 5 and 7/8 = 5 x (7/8)

= 35/8

Reciprocal of 35/8 is 8/35.