How do I find the moles in the Ideal Gas Law?

PV=nRT ... where n is the amount of substance of gas (or moles...as you're asking about) and R is the gas constant, equal to the product of Boltzmann's constant and Avogadro's (or as we called it in Mrs. Ashman's cl, Avocado's number) constant. In SI units, n is measured in moles, and T in kelvin. R has the value 8.314 J·K−1·mol−1.