LCM( 10, 1000 ) = 1000
The formula for finding LCM is
$$ \text{LCM} (a, b) = \frac{ a \cdot b }{ \text{GCD}(a,b)} $$In this example we have: a = 10, b = 1000 and GCD(10, 1000) = 10.
$$ \text{LCM} (10, 1000) = \frac{ 10 \cdot 1000 }{ \text{GCD}(10,1000)} = \frac{ 10000 }{ 10 } = 1000 $$