You can get about 23 Baht for 1 Canadian dollar. So if you see a price like 850 to get the CAD amount you divide it by 23 right?

I don’t know about you, but figuring out 850/23 is pretty slow…

So don’t do that.

Here’s a trick one of my former colleagues (and all around great guy) Klaus showed me:
Instead of doing divisions, do multiplications!

So let’s say I have 23 to 1, instead multiply by 4. Now where the heck did 4 come from you may ask. To get 4 you take 100 and divide it by 23. And yes, that’s not exactly 4, but for our purposes (figuring out roughly how much that coffee costs) it’s close enough. So you take 850 *4. In most cases you just need to take the most significant digit, in this case 8 and do *4. Boom 32$.

(Now yes, it’s actually 36, but it took so much less time and it’s accurate enough for most cases [and yes you technically need to divide by 10, but usually you know if something will be 3,30 or 300$ instinctively so you can skip it)