Home > Pre-Algebra > HCF and LCM of numbers > Least Common Denominator (LCD) example

8. LCD example ( Enter your problem )

1. Examples





1. Find LCD of 12/25,18/45

Solution:
Step-1 : `12/25,18/45`

Step-2 : Find the least common multiple (LCM) of denominators
Here, LCM of `25,45 = 225`

Step-3 :
`:.` Least common denominator (LCD) of `25,45 = 225`

Step-4 : Rewriting the original inputs as equivalent fractions with the LCD:
`25/225,45/225`



Steps of finding LCM of 25,45

Method-1 : Finding LCM of 25,45 using Division Method
Step-1: Divide the numbers by prime factors until the remainder is 1

32545
32515
5255
551
 11


Step-2: Multiply all the divisors to obtain the LCM

LCM of `25,45=3 xx 3 xx 5 xx 5=225`


Method-2 : Finding LCM of 25,45 using Prime Factorization Method
Step-1: Prime factorization of `25,45` using factor by division method

525
55
 1
 
345
315
55
 1

Step-2: Write each number as a product of primes, matching primes vertically when possible
25=5 × 5
45=3 × 3 × 5

Step-3: Bring down the primes in each column. The LCM is the product of these factors
25=5 × 5
45=3 × 3 × 5

LCM = 3 × 3 × 5 × 5 = 225

`:.` LCM of `25,45` is `225`

2. Find LCD of 8/9,32/12,10/15

Solution:
Step-1 : `8/9,32/12,10/15`

Step-2 : Find the least common multiple (LCM) of denominators
Here, LCM of `9,12,15 = 180`

Step-3 :
`:.` Least common denominator (LCD) of `9,12,15 = 180`

Step-4 : Rewriting the original inputs as equivalent fractions with the LCD:
`9/180,12/180,15/180`



Steps of finding LCM of 9,12,15

Method-1 : Finding LCM of 9,12,15 using Division Method
Step-1: Divide the numbers by prime factors until the remainder is 1

291215
29615
39315
3315
5115
 111


Step-2: Multiply all the divisors to obtain the LCM

LCM of `9,12,15=2 xx 2 xx 3 xx 3 xx 5=180`


Method-2 : Finding LCM of 9,12,15 using Prime Factorization Method
Step-1: Prime factorization of `9,12,15` using factor by division method

39
33
 1
 
212
26
33
 1
 
315
55
 1

Step-2: Write each number as a product of primes, matching primes vertically when possible
9=3 × 3
12=2 × 2 × 3
15=3 × 5

Step-3: Bring down the primes in each column. The LCM is the product of these factors
9=3 × 3
12=2 × 2 × 3
15=3 × 5

LCM = 2 × 2 × 3 × 3 × 5 = 180

`:.` LCM of `9,12,15` is `180`

3. Find LCD of 4/5,3/10,7/15

Solution:
Step-1 : `4/5,3/10,7/15`

Step-2 : Find the least common multiple (LCM) of denominators
Here, LCM of `5,10,15 = 30`

Step-3 :
`:.` Least common denominator (LCD) of `5,10,15 = 30`

Step-4 : Rewriting the original inputs as equivalent fractions with the LCD:
`5/30,10/30,15/30`



Steps of finding LCM of 5,10,15

Method-1 : Finding LCM of 5,10,15 using Division Method
Step-1: Divide the numbers by prime factors until the remainder is 1

251015
35515
5555
 111


Step-2: Multiply all the divisors to obtain the LCM

LCM of `5,10,15=2 xx 3 xx 5=30`


Method-2 : Finding LCM of 5,10,15 using Prime Factorization Method
Step-1: Prime factorization of `5,10,15` using factor by division method

55
 1
 
210
55
 1
 
315
55
 1

Step-2: Write each number as a product of primes, matching primes vertically when possible
5=5
10=2 × 5
15=3 × 5

Step-3: Bring down the primes in each column. The LCM is the product of these factors
5=5
10=2 × 5
15=3 × 5

LCM = 2 × 3 × 5 = 30

`:.` LCM of `5,10,15` is `30`





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