In the United States of America, one nickel is equal to five cents (or five pennies). So 1 nickel = 5 pennies and 5 pennies = 1 nickel. To count money when using nickels, just count by 5's.
1 nickel = 5 pennies
2 nickels = 10 pennies
3 nickels = 15 pennies
4 nickels = 20 pennies etc.
You can exchange 5 pennies for 1 nickel, I don't know of anyone thats ever exchanged change for other change personally. Pennies are the lowest worth type of money, they are worth $0.01. A nickel is worth 5 time as much as a penny, being worth $0.05. Making 5 pennies worth one nickel.
...I am going to go with this being a trick question, and therefore will answer with...
ZERO.
There are zero nickels in five pennies since pennies are not nickels.
Five pennies are just one nickel. Five cents is simply five cents, whether it is represented in five pennies, or in one coin.
...