The method is like this:
Coins are identified by three characteristics:
- Size. The dime is the smallest coin, and the half-dollar is the largest.
- Edge. The penny and the nickel have a smooth edge. The dime, quarter, and half-dollar have a milled, ridged edge.
- Thickness. The nickel is thicker than the other coins.
- Leave $1 bills unfolded
- Fold $5 bills lengthwise ("the long way")
- Fold $10 bills by width ("the short way")
- Fold $20 bills lengthwise and then by width ("total fold")