Coins

Usually metal.
Used for money. 
In America the government authorizes these denominations.
Common coins in the United States.
Metal
copper               nickel              silver                   silver
     
Worth

     1 cent              5 cents          10 cents            25 cents

Called
    Penny               Nickel          Dime                Quarter




Sometimes see


Metal
Silver                                       Silver



Worth
50 cents                                         $1.00        
Called

        Half Dollar                                Susan B. Anthony Dollar


http://etc.usf.edu/clipart/galleries/math/half_dollar.php


http://www.usmint.gov/?flash=yes

http://www.myschoolhouse.com/courses/O/1/11.asp

http://www.myschoolhouse.com/courses/O/1/38.asp

http://www.apples4theteacher.com/java/counting/money.html

http://www.canteach.ca/elementary/songspoems70.html