Math matters … no really, it does.

When you’re visiting a new country, Rick Steves and Elizabeth Gilbert, among other travel experts, always recommend you immerse yourself in the culture.

For most tourists, this means experiencing the food, the sights, the language and even the transportation the way a local would. However, to truly dive into another country’s practices, you also have to make sure your math skills aren’t too rusty.

Hear me out … To enjoy a hearty order of beef goulash in Prague, you not only have to be able to convert Czech koruna to dollars, you also have to understand whether you’re paying too much for the meal in the first place.

Jakub Flkejzl, FAC program assistant for Council on International Education Exchange (CIEE), cautioned against spending more than 160 Kč for a meal with sides at lunch. In dollars, this comes out to around $8 –– which won’t even buy a chicken burrito with guacamole at Chipotle –– but in the Czech Republic, this is the price of a reasonable meal.

Regardless of where you travel, it just makes sense that when you engage in another country’s customs, you should also keep up with their currency, and how it converts to your own. Treating yourself every now and again is just fine, but to really act like a local, you’ve got to spend like a local.