What is the lowest common multiple of 8 and 10 how is it 40?

Least common multiple of 8 and 10 is 40 that's like this

write down multiples of the whole number 8 first, they are

8,16,24,32,40,48,56,64,72,80,88 etc..

now write down multiples of the whole number 10,they are

10,20,30,40,50,60,70,80,90 etc......

as you can see 40 and 80 are common multiples in the series

but 40 is the smallest one hence it is the LCM of 8 and 10