How many moles of caco3 are there in an antacid tablet containing 0.515 g caco3?

The moles of CaCO3 which are there in antacid tablet that contain 0.515g CaCO3 is calculated as follows

moles = mass/molar mass

the molar mass of CaCO3 = (40 x1) + (12 x 1) + (16 x 3) = 100 g/mol

moles is therefore = 0.515g/100 g/mol = 5.15 x10^-3 moles