LCM( 7, 12 ) = 84
The formula for finding LCM is
$$ \text{LCM} (a, b) = \frac{ a \cdot b }{ \text{GCD}(a,b)} $$In this example we have: a = 7, b = 12 and GCD(7, 12) = 1.
$$ \text{LCM} (7, 12) = \frac{ 7 \cdot 12 }{ \text{GCD}(7,12)} = \frac{ 84 }{ 1 } = 84 $$