You need at least two fractions to determine a least common denominator.
34
The LCD for 17 and 12 is 204
204
The only Least Common Multiple (LCM) for 17 16 is 272.
Their product.
A common denominator, though not the least, is 1700.
You need at least two fractions to determine a least common denominator.
136
68
It is 85
119
34
The LCD for 17 and 12 is 204
204
A single number cannot have anything in common. To find a lowest common denominator, you need to be adding or subtracting at least two fractions.
LCD(17, 19) = 323