MATH: ALSO GOOD FOR CATCHING THIEVING WAITERS

[defrog]

ITEM: One form of small-scale credit card fraud is when waiters add an additional tip in the tip line of yr credit card (even if you’ve left a cash tip on the table) – by, say, turning a 3 into an 8 with a stroke of the pen, or adding a “1” in front of a “5.71” tip (though that's admittedly not easy if they put a dollar sign right in front of the amount).

Naturally, you can prevent this by keeping the paper receipt and checking them against yr credit card bill, but if yr not in the habit of keeping yr credit card receipts – or prone to losing them – Punny Money recommends using a checksum technique.

Say this is yr bill.

Adjust the amount of the tip so that the numbers in the final total to the left of the decimal point add up to the right-most digit. In this case, the total has a “51" to the left of the decimal point (A). 5 + 1 = 6, so the final digit should be six. Adjust the total to $51.86 or $51.96 (B) by adding nine or subtracting one from the tip (C).

Then, when you get the credit card statement, find the item and add the numbers to the left of the decimal point, and confirm that they add up to the right-most digit. If they don’t, you’ve been pwned. It’s not 100% foolproof, but it can help keep yr losses low.

If yr not mathematically inclined but you do have an iPhone or a smartphone running Windows Mobile, there are apps for both that can calculate a checksum tip for you.

Speaking of handsets, Free From Broke has another suggestion: if you have a mobile phone with a camera, use it to take a photo of all your credit card receipts as soon as you get them. That way, you'll have a dated record of all your credit card purchases that you can refer to when you go over your credit card statements.

Wow. Who knew math would be this useful?

NOTE: Many people would also argue that one way to prevent this is to tip servers 20% like yr supposed to. Maybe – but while I wouldn’t exactly say I take all my tipping advice from Steve Buscemi, I do think tipping shouldn’t be automatic. And waiters rude enough to not be worth tipping might also be the sort to resort to credit card fraud to get revenge on deadbeat customers.

Being with me is like math class,

This is dF

Comments

[thelastaerie.livejournal.com]

Tipping in US makes me nervous, I never really sure who I should tip (the door man? the bell boy? every time? the guy who open your cab door? the helpful receptionist?)... cab drivers?

it's actually fairly straight forward in restaurants - someone told me to take the tax amount times 2 for tips, that would be something like 16-20% (depends on the state?) And to be honest, the whole tipping system makes me suspicious about waiters' "nice attitude". While I know there's nothing wrong working for your tips, but I do prefer the "no tipping but still great service" way they have in Japan.

It's a job - their employers should compensate them properly in the first place!

[def-fr0g-42.livejournal.com]

Same for me – apart from restaurants, I never know how to tip in the states, not least because it seems to change all the time without warning – for example, I was never notified when everyone decided that it should go from 10% to 15%, then from 15% to 20%, etc. I prefer Asia where they just add 10% to yr bill and be done with it.