Figure out the exchange rate

No problem if math is not your thing. Figure out the foreign equivalents of frequently used denominations, so you are not going around trying to pay $20 dollars instead of $2 for a bottle of water. For most of us, knowing the equivalents of $1, $10 and $100 is adequate. Even if you are using a credit card for most purchases while traveling abroad, its important to understand how many zeros equal your price point!