LCM( 6, 30 ) = 30
The formula for finding LCM is
$$ \text{LCM} (a, b) = \frac{ a \cdot b }{ \text{GCD}(a,b)} $$In this example we have: a = 6, b = 30 and GCD(6, 30) = 6.
$$ \text{LCM} (6, 30) = \frac{ 6 \cdot 30 }{ \text{GCD}(6,30)} = \frac{ 180 }{ 6 } = 30 $$