Calculating the tip is a great way to practice percentages. These days, I don’t think many people do much math with a pencil and paper. We rely on technology for almost everything — even things as simple as calculating the tip at a restaurant are now done with a tablet on the table or an app on your phone.

I think it’s important, however, to put the technology aside for a bit and work through a problem by yourself. That’s what we’ve been doing here for awhile — by keeping account registers, learning how to calculate percentages, practicing those calculations, and even tracking our spending on vacation. All with pencil and paper. Old school.

My favorite lessons are those that he can practice himself (hands-on!), that make sense in the real-world (are meaningful, relatable and useful), appropriate for his age and are interesting and even fun. (I realize I *may* be stretching the definition of fun.)

In that vein, I taught J how to calculate a 20% tip at a restaurant.

## 4 Easy Steps to Calculate the Tip

- Write the total on the back of the receipt (where there’s room to work)
- Move the decimal place one to the left (I like to draw a big arrow)
- Round the number (this was a bit of a sticking point, rounding to the correct number of digits)
- Add it to itself to get a 20% tip

And then of course, write the tip on the front and add to get the total. Bam. Magic. Math magic. You’re a math magician.

I have been keeping restaurant receipts lately so that he can practice on those. (Normally I write the tip and total on them so I can enter them in my checkbook when I get home — yes, I’m *that* person — but I’ve been leaving these blank so J can write on the front.)

There are other ways to calculate the tip (thanks Business Insider and Math Dude!) that you may find helpful. The thing about math is that there’s often not just one way to solve a problem. If one way doesn’t make sense, search for another way that works for you.