Since 20 is a multiple of 5, it is automatically the LCM. No workings necessary.
The LCM of 4 and 5 is 20.
LCM(4, 5, 10) = 20
LCM(4, 5) = 20.
The LCM is 40.
The LCM is 100.
The LCM is 20.
The LCM is 20
The LCM is 20.
The LCM is 60.
The LCM is 40.
LCM of 16, 5, and 20 = 80
The Lowest Common Multiple (LCM) of 4, 5 and 10 is 20