Answer:
I'm pretty sure its just the mass of the sample divided by the molar mass
for example if I had like 7g of carbon and wanted to find the moles, I would divide the mass I have (7g) by the molar mass (the atomic mass value on your periodic table, in this case for carbon it would be 14g)
moles = [tex]\frac{mass}{molarmass} = \frac{7}{14} = 0.5\ moles[/tex]
Hope this helped