Definitions by Numerati

Purrfect Number

The number of cats or kittens a pet lover could own based on their financial situation that would allow them to lovingly care for them, space constraint to house them, or national law that lays down how many feline members they could live with.

The purrfect number in every country varies, depending on a number of factors like geography, social responsibility, and religious views towards the feline community.

Purrfect Number by Numerati December 18, 2025

Piism

A popular faith among mostly male geeks or pi zealots, who enter the name in the “other religions” category when filling out a printed or digital form.

At the last census, Piism had made some numerical progress, by breaking the psychological barrier of 3,141 diehard believers.

Piism by Numerati November 20, 2025

6-7

When puritan parents are asked by their kids what the number sixty-nine means, they pretend they misheard it as sixty-seven, so they start chanting “six-seven, six-seven, six-seven” repeatedly—each time louder and faster—until the young ones start parroting it too.

In strict Singapore schools, where grades K–12 students generally respect teachers, some mean or no-nonsense educators vow to kick out rude or cheeky kids who’re caught saying or swearing 6-7 in class.

6-7 by Numerati November 17, 2025

Banana Pi

The title of a contemporary artwork by a maverick artist, with the number π in different typefaces and fonts randomly spread out on the skin of a banana, whose starting price at an upcoming auction is forecast to be at least US$3.14 million.

A billionaire felon who’s recently pardoned for his years-long crypto crimes is rumoured to be a potential buyer of “Banana Pi,” with the plan to donate it to a presidential library.

Banana Pi by Numerati November 1, 2025

Piradise

Short for “Pi Paradise.” A glimpse of what the number π would look like for geeks, whose names would make it in the Book of Life, albeit the chances for a large percentage of them getting into heaven are disproportionately lower than those who were not born or blessed with the “math gene.”

What percent of mathematicians and math educators worldwide might fail to experience piradise after their last heartbeat on this side of heaven?

Piradise by Numerati October 27, 2025

Singapore Math

A girly form of practical pseudo-street math promoted on social platforms like TikTok and Instagram, which makes someone feel that they are getting a good deal or bargain, or that they are smartly saving rather than splurging their cash away.

“Singapore Math” is a cousin of “Girl Math.” It’s like freely or unashamedly taking home a dozen-plus sachets of sugar, salt, ketchup, and chili sauce from McDonald’s, when you’ve only ordered the cheapest set meal on offer.

Singapore Math by Numerati October 24, 2025

Sky in the Pi

When some colored or shaded digits of the number π listed on a canvas or cardboard reads or looks like the ghostly or imaginary word “sky.”

When Paul asked Timothy whether he saw the “sky in the pi” on the huge poster, his geeky friend thought he misspoke the term “pi in the sky.”

Sky in the Pi by Numerati October 21, 2025