What is the LCM of 6 and 6.5?

Answer 1

There is no such number.

The concept of factors and multiples works for integers. Once you introduce fractions things no longer work. Any fraction is a multiple (a fractional multiple, maybe) of any other number.

So for example, lets say 2.4

2.4 is a multiple of 6 since 6*(2.4/6) = 6*(24/60) = 2.4

and

2.4 is a multiple of 6.5 since 6.5*(2.4/6.5) =6.5*(24/65) = 2.4

So 2.4 is a common multiple.

Similarly, 0.24 can be shown to be a multiple, and then 0.0024 and so on and on.

Answer 2

The LCM applies to integers, not decimals.