As a historical note...I was in Britain just after decimalization day (which was as I remember 26 April 1971)...what they did to help people understand conversion is many of the coins were kept legal tender (whtever that means) and their replacement coins were exactly the same size (boy were some of them large)...thus the one shilling coin remained for a while, its replacement was the 5p coin and it was the same exact size. Same held for the 10p coin (the new one replaced the 2 hillingt coin but the 2 hillingt coin remained in circulation for a while and counted as 10p)...they did retain the 6d coin which was 2 1/2 new pence (2 1/2 p today) although they did not mint a replacement coin...it wasn't till some time in the 80's that the large coins were replaced by what they have today.

For some more information that might be interesting to your class, take a look a the website from the Geld (money) Museum in Frankfurt. And if you are ever in town, the museum is free.
http://www.geldmuseum.de/index.en.php

Yes it comes back now...I do remember my first trip on the London Underground from Picadilly to Bayswater...fare was 1 shilling (5p)....gave the clerk in the booking hall a £1 bank note (they existed in that day anad age and they didn't take credit cards then) and got back 9 10p coins and one 5p coin...when I put them in my pocket I knew then why the monetary unit in Britain was called the pound!

xyz123, correct, all our silver coins were directly interchangable with their decimal equivalents for some years. Since then they have shrunk, along with their values. The present tiddly little 5p coin, which used to be a shilling, makes a very good ball marker on a golf course. The advantage of it being virtually worthless is that if you lose it your loss is minimal.

I have coined (heh-heh) a neologism for new pence: nuppence (by analogy to the old two pence = tuppence).

About five Brits in seven get it.