speed
you can just use your brain to find the LCM faster, sometimes.
31 is already prime; no method required.
The prime factorization of 27 is 3 x 3 x 3.
139 is already prime; no factorization required.
ewan
145 5,29
it is fast and easy
It is: 7*7 = 49
The concept of "prime factorization" is used for integers. It doesn't make sense to use it for fractions or decimals.
2, 5 and 7
22*3 = 12
It is: 3*3*5 = 45
It is: 30