LCM( 3, 1 ) = 3
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 = 1 and GCD(3, 1) = 1.
$$ \text{LCM} (3, 1) = \frac{ 3 \cdot 1 }{ \text{GCD}(3,1)} = \frac{ 3 }{ 1 } = 3 $$