What is an exchange rate?

An exchange rate is a dynamic ratio between different forms of currency and is determined by respected treasuries and the foreign exchange market.

Can you simplify that for my remedial brain?

It's a rate for converting currency that always changes. It's also controlled by governments and international trading.

Why does it constantly change?

Many factors contribute to this, but the concepts behind revolve around an idea of supply and damand. This would include amount of currency in circulation, inflation, and other political and economic conditions.

I am travelling to a counrty that uses ___. How do I convert my cash while abroad?

Many banks and ATMs can automatically do the currency conversion when you use your credit/debit card. There are also a few cities with "currency houses," but you are better off with the ATM.

How can I find out the exchange rate?

Use the internet. This website as well as others have a real time currency converters to help find exchange rates.

Thanks Einstein, but I don't have internet. Now how do I find out the exchange rate?

Either call your bank or the Department of the Treasury. Both should be up to date with current exchange rates.

I just arrived at the airport and both my passport and cash are invalid.

Please watch The Terminal (2004) for more details.