This game site has a section called Money Master. Within this page you can select the currency you wish to work with. Select the level of difficulty and math the coins to the amount it asks. The skill game is timed. There are other pages that cover Algebra, Geometry, Data, Measurement and Numeration that test the students’ skills. You can also find Math and logic puzzles.
http://www.mathsisfun.com/money/money-master.html