1. Convert $15 to quarters. You can do this by multiplying 15 by 4. You use 4 because 4 quarters equal to $1. This will equal to 60 quarters.
2. Multiply both 5.76 and 6.25 by 60 to find the weight of $15 in quarters for today and before 1965. Today: 5.76 g x 60 = 345.6 grams Before 1965: 6.25 g x 60 = 375 grams
3. Now that you have the weight of quarters for both time periods, subtract! 375 grams - 345.6 grams = 29.4 grams
