LCM( 24, 28 ) = 168
The formula for finding LCM is
$$ \text{LCM} (a, b) = \frac{ a \cdot b }{ \text{GCD}(a,b)} $$In this example we have: a = 24, b = 28 and GCD(24, 28) = 4.
$$ \text{LCM} (24, 28) = \frac{ 24 \cdot 28 }{ \text{GCD}(24,28)} = \frac{ 672 }{ 4 } = 168 $$