_Gold_: Sovereign, half-sovereign, and guinea, which is equal to 21
shillings.
_Silver_: The crown (equal to 5 shillings), half-crown, florin (equal to
2 shillings), shilling, six-penny and three-penny pieces.
_Copper_: Penny and half-penny.
EXAMPLE: I have £5 sterling. What is the value in United States money?