Addition of Unlike Fractions

We will learn how to solve addition of unlike fractions.

In order to add unlike fractions, first we convert them as like fractions with same denominator in each fraction with the help of method explained earlier and then we add the fractions.

Let us consider some of the examples of adding unlike fractions:

1. Add 7/8 and 9/10

Solution:

The L.C.M. of the denominators 8 and 10 is 40.

7/8 = (7 × 5)/(8 × 5) = 35/40 , (because 40 ÷ 8 = 5)

9/10 = (9 × 4)/(10 × 4) = 36/40, (because 40 ÷ 10 = 4)

Thus, 7/8 + 9/10

= 35/40 + 36/40

= (35 + 36)/40

= 71/40

= 1 31/40

2. Add 1/6 and 5/12

Solution:

Let L.C.M. of the denominators 6 and 12 is 12.

1/6 = (1 × 2)/(6 × 2) = 2/12, (because 12 ÷ 6 = 2)

5/12 = (5 × 1)/(12 × 1) = 5/12, (because 12 ÷ 12 = 1)

Thus, 1/6 + 5/12

= 2/12 + 5/12

= (2 + 5)/12

= 7/12

3. Add 2/3, 1/15 and 5/6

Solution:

The L.C.M. of the denominators 3, 15 and 6 is 30.

2/3 = (2 × 10)/(3 × 10) = 20/30, (because 30 ÷ 3 = 10)

1/15 = (1 × 2)/(15 × 2) = 2/30, (because 30 ÷ 15 = 2)

5/6  = (5 × 5)/(6 × 5) = 22/30, (because 30 ÷ 6 = 5)

Thus, 2/3 + 1/15 + 5/6

= 20/30 + 2/30 + 25/30

= (20 + 2 + 25)/30

= 47/30

= 1 17/30

Related Concept

● Fraction of a Whole Numbers

● Representation of a Fraction

● Equivalent Fractions

● Properties of Equivalent Fractions

● Like and Unlike Fractions

● Comparison of Like Fractions

● Comparison of Fractions having the same Numerator

● Types of Fractions

● Changing Fractions

● Conversion of Fractions into Fractions having Same Denominator

● Conversion of a Fraction into its Smallest and Simplest Form

● Addition of Fractions having the Same Denominator

● Subtraction of Fractions having the Same Denominator

● Addition and Subtraction of Fractions on the Fraction Number Line

4th Grade Math Activities

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