**Definition of Least Common Denominator (LCD)**

- Least Common Denominator is the least common multiple of two or more of fractions.

**More about Least Common Denominator (LCD)**

- It is also called as lowest common denominator.
**Steps to find the Least Common Denominator:** 1. First find the multiples of the denominators.

2. Identify the least common multiple.

**Example of Least Common Denominator (LCD)**

- To find the least common denominator of the fractions and , first we need to find the multiples of the denominator 7 i.e. 7, 14,
**21**, 28, 35 . . . and the multiples of the denominator 3 i.e. 3, 6, 9, 12, 15, 18,**21**, 24 . . . The least common multiple of the denominators 7 and 3 is 21.

So, the least common denominator of the fractionsand is **21**.

**Solved Example on Least Common Denominator (LCD)**

Find the least common denominator of the given expression.

+

Choices:

A. 12

B. 16

C. 4

D. 21

Correct Answer: A

Solution:

Step 1:The denominators of the given fractions are 4 and 12.

Step 2:Multiples of 4 are 4, 8, 12, 16, 20 . . .

Step 3:Multiples of 12 are 12, 24, 36, 48 . . .

Step 4:The lowest multiple the numbers have in common is 12.

Step 5:So, the least common denominator of the given fractions is 12.

**Related Terms for Least Common Denominator (LCD)**

- Common multiple
- Denominator
- Greatest Common Factor
- Least Common Multiple (LCM)
- Multiple