How do make a dollar out of 21 coins?

One dollar can be made by adding the values of the following 21 U.S. coins:

10 pennies (10 ¢)

7 nickels (35 ¢)

3 dimes (30 ¢)

1 quarter (25 ¢)

There are also many other possible configurations including:

10 pennies (10 ¢)

4 nickels (20 ¢)

7 dimes (70 ¢)

and

5 pennies (5 ¢)

13 nickels (65 ¢)

3 dimes (30 ¢)