A common denominator of 20 and 30 is 600. This is NOT the least common denominator, though.
The least common denominator (LCD) is 1.
A common denominator, though the least, is 260.
20 is.
20
It is: 20
A common denominator, though not the least one, is 12*20 = 240.
20
20
The answer is 220
40
40