Closing time has a remarkable talent for attracting the strangest customer interactions.

How do three one-dollar items somehow become an unacceptable three-dollar total?

One shopper challenged the cashier’s arithmetic with absolute confidence and very little supporting evidence.

Check out how the numbers struck back.

Woman did not understand 2+1=3

Store is close to closing and I’m running register.

A woman has 2 canned vegetables and a soda. Each are a dollar ($1.09 with tax).

I ring up the cans and she asks if they’re 2 for $2, which I confirm they are. Nothing unusual, as the deal is promoted next to the tag for all of our generic brand canned vegetables.

But soon, an amusing misunderstanding unfolds.

I then continue and ring the soda up.

Me: “Alright ma’am, your total is $3.26.”

Woman: “How is it 3 dollars if the two cans are $1 each?”

The cashier patiently breaks it down for her.

Me: “You also have a soda, ma’am, which is a dollar, so that makes it $3. $3.26 with tax.”

The woman then repeats herself, so I do the same.

Woman: “OK, I’m just going to stop—sorry, I’m right.”

She then pays. I say, “Have a good night,” and I continue on with my night, albeit a little confused how someone didn’t understand 1+1+1=3.

Math can be tough, but this is about as simple as it gets.

What did Reddit think?

Perhaps a severe lack of sleep is to blame here?

Or maybe math just isn’t as prioritized nowadays.

This story didn’t sit right with this commenter.

If you enjoyed this story, check out this post about an employee who gets problematic overtime changes reversed by pointing out how it will harm the company’s bottom line.

Any customer service employee will be quick to tell you that customers have been known to not read.

The cashier repeatedly explained that two canned vegetables plus one soda totaled three dollars before tax.

Although the customer insisted she was right, she ultimately paid the correct amount and left.

Somewhere between the canned goods and the soda, the number three became a controversial accounting theory.