LCM( 64, 124 ) = 1984
The formula for finding LCM is
$$ \text{LCM} (a, b) = \frac{ a \cdot b }{ \text{GCD}(a,b)} $$In this example we have: a = 64, b = 124 and GCD(64, 124) = 4.
$$ \text{LCM} (64, 124) = \frac{ 64 \cdot 124 }{ \text{GCD}(64,124)} = \frac{ 7936 }{ 4 } = 1984 $$