How many moles of atoms are in 500.00 mg of calcium?

Calcium hydroxide (Ca(OH)2) has a molar mass of 74g/mol. To find the number of moles in 0.5000g of calcium hydroxide, you divide the 0.5000gCa(OH)2 by 74gCa(OH)2. The answer is 0.006757mol Ca(OH)2 to the nearest significant figure.