So, the next topic I'll be teaching my student is percent. Before we start cranking the Singapore Math, I plan a little dialogue like this:
Q. Why do we call pennies "cents"?
A. Because there are 100 to the dollar.
Q. How many years in a century?
Q. What does "cent" mean?
Q. What does "per cent" mean?
A. "for 100".
Digression (if we have time):
Q. British money also contains pennies, but they are never referred to as "cents". Why?
A. Because, historically, there were more than 100 pence to the pound. For centuries, Britain had a system where there were 20 shillings to the pound, and 12 pence to the shilling.
Q. How many pence were there to the pound?
A. 12 x 20 = 240.
Since 1971, Britain has been using a modernized currency, so they now have 100 pence to the pound.
Extra credit for old folks (I might ask my student's parents): what Beatles song contains an oblique reference to the old currency system?