Proof for the conversion of nanometers to inverse centimeters

Question

This is probably an elementary question, but I can't seem to figure it out. How does one convert nm to inverse cm?

For example, if I start with 10 nm, my first step would be to flip the fraction so it becomes 1/(10 nm)then just proceed normally. But I end up getting the wrong answer...

Answer 1

You don't, any more than you convert metres to kilograms. They are different dimensions.