The UK's currency is the pound sterling, written with the symbol £. One pound is worth 100 pence (written "p" for short).
The 8 coins and 4 notes in everyday use (a rough sketch: sizes and colours are only approximate). The 20p and 50p coins have seven sides, so they're easy to spot.
Banks in Scotland and Northern Ireland print their own banknotes, with designs that differ from Bank of England notes. These notes are valid all over the UK, but a shop or business can choose not to take them. So don't be surprised if a shop assistant in London looks twice at a Scottish note.
Quiz
Which of the following statements is correct?
Scottish and Northern Irish notes can be used anywhere in the UK; a shop is simply allowed to say no. Option A mixes up "a shop may refuse them" with "they only work in Scotland".