Pick two of the fractions and find the Least Common Multiple of those two denominators. Then take that number, and find the Least Common Multiple between that and the third denominator. This number will be the Least Common Denominator between the three fractions.If you don't care to find the Least common denominator, then just take the three denominators, and multiply them together.
LCM(3, 4, 5) = 60
Suggestion: Find the least common multiple using your favorite method (for example, prime factorization). Then multiply that by 1, by 2, and by 3, to get your answer.
105
The least common multiple of 9, 36, and 60 is the smallest number that can be divided by each of the three numbers without a remainder. In this case, the answer is 180. (180/60 = 3, 180/36 = 5, and 180/9 = 20)
21
119
63
84
3 * 7
LCM: 42
The LCM is: 210
The LCM is: 54
21 is the LCM of 3 and 7.
420
The Least Common Multiple (LCM) of (54,63) is 378.
3 * 35 = 5 * 21 = 7 * 15 = 105