Strategy Hint 1: It is easiest to solve this type of problem by staying organized! Start listing the answers with the highest value coin (one quarter), then list the next highest value coins (2 dimes and 1 nickel) and end with the smallest value coins (25 pennies). By solving the problem this way, you are less likely to leave out answers!
Strategy Hint 2: Using symbols like Q, D, N and P to represent the names of the coins will make it even easier to write all of the combinations. (Example: 3N, 10P means 3 Nickels, 10 Pennies)