In the equation

x = n / f

n is 1 kg m^-2 and f is 1 kg m^-1

What is x?

This is just confusing my poor brain, any help to understand would be much appreciated.

I put what I thought the answer was as x = 1 kg m^2 but I'm told the numerical value is correct but the unit is incorrect, am I being stupid here or am I missing something blatantly obvious?

Thanks for any help regarding this.