[Maths Class Notes] on Reciprocal and Division of Fractions Pdf for Exam

Reciprocal and Division of fractions are different from each other. When two terms, such that the second is the inverse of first, gives a product of 1 upon multiplication, then the fractions are called reciprocal or multiplicative inverse of each other. It can be achieved by interchanging the numerator and denominator of the fraction. If a term is x/y, then its reciprocal will be y/x. A fraction is a numerical quantity that represents a part of the whole number.

Dividing fractions requires inverting the divisor (reciprocal of the divisor) and then follow the steps of multiplication. The term x/y, when divided by a non-zero fraction p/q, then the expression looks like:

x/y ÷ p/q = x/y ÷ q/p

Division of fractions involves multiple steps.

Parts of Fraction

The parts of a fraction are:

• Numerator: The numerator is the number which is on the top of the line. It shows how many equal parts of the whole or collection is taken.

• Denominator: The number below the line is the denominator. It shows the total divisible number of equal parts or the total number of equal parts which they are in a collection.

Types of Fraction

There are three different types of fractions:

Example: 4/5, 1/6, 7/9, 3/7, etc.

Example: 5/2, 7/3, 8/5, 5,3, etc.

Example: 4²/₃, 3¹/₂, etc.

Reciprocal of Fractions

Interchanging or swapping the numerator or denominator with each other gives us the reciprocal of the fraction. Like for example, the reciprocal of 1/2 is 2/1, or that of 4 is 1/4.

In order to obtain a reciprocal from a mixed fraction, it must be converted to an improper fraction, and then the numerator and denominator must be swapped. For example, to find the reciprocal of 4²/₃, it is first converted into an improper fraction.

4²/₃ =14/3[improper fraction]

14/3 = 3/14

Therefore, the reciprocal of 4²/₃ is 3/14.

The product of a fraction and its reciprocal is always 1, as it is nothing but its inverse.

Division of Fractions

Division of fractions involves certain rules and follows multiple steps. To perform Division, we have to multiply the first fraction with the reciprocal of the second. Division involves some steps to be followed:

• Step 1: Changing the division sign (÷) to the multiplication sign (×).

• Step 2: If we change the sign to multiplication, we also have to write the reciprocal of the second term or fraction.

• Step 3: Multiplying the fractions and simplifying the result.

Here, is an example of Division of fractions:

15³/₇ ÷ 1²³/₄₉

First, we have to change the mixed  to an improper fraction.

= 108/ 7 ÷ 72/49.

Step 1: Changing the sign to multiplication from division and writing the reciprocal of the second term [72/49 = 49/72]

 = 108/7 × 49/72

Step 2: Multiplying the first with the reciprocal of the second fraction.

= (108 × 49)/ (7 × 72)

= (3 × 7)/ (1 × 2)

= 21/2

Step 3: Getting the simplified result of the expression.

Division of fractions is the multiplication of fractions by just changing the second fraction to its reciprocal.

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Solved Example:

1. 5/9 ÷ 2/3

[Step I: Turning over the second fraction upside-down (it becomes a reciprocal): 2/3 becomes 3/2.]

= 5/9 × 3/2 

 [Step II: Multiplying the first fraction by the reciprocal of the second: (3 × 5)/(2 × 9)]

= 5/6 

[Step III: It is the simplified expression, hence no further simplifications].

2. 4/9 ÷ 2/3

[Step I: Turning over the second fraction upside-down (it becomes a reciprocal): 2/3 becomes 3/2.]

= 4/9 × 3/2

[Step II: Multiplying the first fraction by the reciprocal of the second]

= (4 × 3)/ (9 × 2)

= (2 × 1)/(3 × 1)

= 2/3

[Step III: It is the simplified expression, hence no further simplifications]