LCM( 3, 4 ) = 12
The formula for finding LCM is
$$ \text{LCM} (a, b) = \frac{ a \cdot b }{ \text{GCD}(a,b)} $$In this example we have: a = 3, b = 4 and GCD(3, 4) = 1.
$$ \text{LCM} (3, 4) = \frac{ 3 \cdot 4 }{ \text{GCD}(3,4)} = \frac{ 12 }{ 1 } = 12 $$