If we use no quarter or dimes, then we can use from 0 through 5 nickels, and the rest pennies. That's 6 ways. If we use no quarter and 1 dime, then we can make the remaining 18 cents using from 0 through 3 nickels, and the rest pennies. That's 4 ways. If we use no quarter and 2 dimes, then we can make the remaining 8 cents using 0 or 1 nickel, and the rest pennies. That's 2 ways. If we use a quarter, then we can only make the remaining 3 cents using 3 pennies. That's 1 way. Total: 6+4+2+1 = 13 ways. Edwin