Terry O'Reilly

As Bellows says, a classic example is Levi's 501 jeans.

It's not Levi's 500 jeans.

It's one better.

It suggests a little extra button here, a little extra bit of sewing there, a mystical added element.

That's not to say round numbers don't have juice.

An anti-dandruff shampoo was searching for a memorable name.

It came down to two choices, either Zinc 24 or Zinc 31.

When both names were tested, respondents overwhelmingly chose Zinc24.

So much so, they were willing to pay 10% more for it.

When that decision was analyzed, it was determined that people prefer the number 24 because they are more familiar with the number from their school days.

In math class, 3 times 8 equals 24 and 4 times 6 equals 24 was drilled into your head.

The number 31 wasn't.

That means we process the number 24 more fluently, and therefore it gives us the feeling that we like it more.

In another experiment, two names for a brand of contact lens were tested, Solace 36 and Solace 37.

The tagline on the packaging said, six colors, six fits.

Respondents overwhelmingly chose Solace 36 because, in their minds, they did the math.

6 times 6 equals 36.

The name and the tagline were arithmetically related.

The pleasure rush from subconsciously doing the math makes us feel good, and we misattribute the buzz as satisfaction with the product.

Yep, math is intriguing.