These days, it’s rare to see anyone other than school kids using a calculator, especially since we can easily crunch numbers on our computers and phones. But, chances are you’re not always traveling with your computer/phone, and this is where a mini calculator can really come in handy.

First up, calculators are great for converting currencies – whether you’re changing money, or just trying to understand how much something actually costs (100 Hong Kong dollars sounds like a lot until you realize it’s only $12.85 US), carrying a calculator and doing the math yourself can save you from being ripped off.

A calculator is also useful to have when you’re faced with having to bargain with local vendors and neither of you speak more than a few words of the same language. You can simply point to the items you want, type a number into your calculator, then hand it to the vendor and let them make a counter-offer. Sometimes shopkeepers will have a calculator handy for this reason, but not always, so it’s good to carry your own. I realize you could also write the numbers down on a piece of paper, but I’ve found people don’t always write using roman numerals, or they have a confusing system of expressing amounts – yet somehow they understand the digital readout on a calculator display. Go figure.

Anyway, the point is to just carry a small calculator for these occasions – I have a teeny one that is on a keychain and it is infinitely useful.