Three math wrongs = pants for $17 a pop.

I need new pants.

That is, I NEEDED new pants, and now I don't need to buy any again for the next 10 years.

I go to unnamed retail chain this morning to look at some pants. I don't usually go here, buy I've heard people rave about their pants. Even the girl at Club Monaco (where I bought three pairs of pants.... I LOVE Club Monaco) said that she gets her pants at this particular mall-rat favorite.

The pants are normally $70 - $80. They fit like a glove, and they're on sale for $30. I pick out 5 pairs, thinking that I would take them home to make the final decision. The guy in the fitting room says "They're 20% off the sale price, and if you open a credit card, you'll get an additional 15% off. That's 35% off!)

I smile.

Because he's wrong. Percents don't add that way.

If an item is on sale for 20% OFF, then you're paying 80% OF (100% - 20%) the sale price. That means that if you're getting 20% off, and then an additional 15% off, then that's the same as (.80)(.85)=.62 of the price, which is really only 32% off.

Granted, this is a marginal amount. On a $100 purchase, it's only $3 difference. But the greater the amount of sale, the greater the error. On $1000 purchase, there's a $30 difference.

I knew the cash register is programmed to get the answer right, anyway. Total cost of my purchase: $115.

I happen to walk by another store of the same chain, and see two more I want to add to the collection I'm now bringing home, sure I'll return at least three of them.

The girl at the register says, "Everything today is 30% off, and then an additional 15% off for opening your credit card. That's 45% off!

I can't let this go anymore. I explain to her that 15% off a 30% off purchase is not 45% off. She is reluctant to believe me. I finally convinced her. Total cost of the two pairs of pants: $36.

I think to ask the manager if the sale is the same for all of the stores, because I only got 20% of at the other store. He offers to do a price change.

The original cost of the 5 pants at the first store was $170. After 20% off, $136. After the additional 15%, $115. If they did it right, it would have been $170, after 30% discount, $119, after additional 15%, $101.

So they owed me about $14.

Instead, the guy returns the 20% discounted pants, $136, which is correct. He rings up the $136 again, and takes 10% off of THAT to "total" 30%. This is WRONG. Taking an additional 10% off 20% discounted merchandise does not equal taking 30% off the original for the same reason. Percents still don't add! Except this time, it counts AGAINST me. $3 worth.

I don't even have a chance to think about this, because the cashier tells me that $32 is going to be returned to my card.

$32??

It turns out that he returned the $136 to my card and forgot to "return" the $20 of discount that I received on the pants!

Not for a second did it seem to occur to this cashier that $30 is a lot more than a 10% error on $115.

Perhaps it was unscrupulous of me to not point out his error, but I was done educating for the day.

Three errors for mall store, and I pay $119 for 7 pairs of pants. That's $17 a pop.

And now I don't feel like I can return them!!!