In nature, 1.07% of the atoms in a carbon sample are c-13 atoms. show a numerical setup for calculating the number of c-13 atoms in a sample containing atoms of carbon.

If we let x be the number of sample which contains the atoms of carbon (C). Given that according to study, the amount of atoms in carbon sample that are C-13 atoms is 1.07%, the mathematical set-up that would represent the sample is,
                               = (0.0107)(C)

That is a lot of moles that you have