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The Rest Is Science
The Rest Is Science

Is 100 Better Than 101?

November 01, 2026 • 44m

Summary

⏱️ 8 min read

Overview

Michael Stevens and Hannah Fry celebrate their 100th episode by debating whether 100 or 101 is the better number. The conversation explores mathematical properties, historical context, human psychology, and even Roman numerals, with Michael arguing for 101's superiority due to its prime status and palindromic nature, while Hannah defends 100 as psychologically significant and deeply embedded in human culture and nature.

The Great Hundred: Historical Origins of 100

The hosts dive into the etymological history of the number 100, discovering that it wasn't always the number we know today. In northern Europe, 'hundred' originally meant 120, known as the 'long hundred' or 'great hundred,' which equals six score (six groups of 20). This historical context reveals how our modern 100 is actually the 'short hundred,' and remnants of this old system persist in measurements like the British hundredweight of 112 pounds.

  • In Old Norse, 100 originally meant 120, called the 'long hundred' or 'great hundred'
  • Modern 100 is actually the 'short hundred,' representing just five score (5 × 20)
  • The British hundredweight is 112 pounds, possibly a remnant of the old Norse hundred
  • Tolkien referenced this in The Hobbit with Bilbo's 'eleventy-first' birthday party
" 100 used to be bigger. They don't make 100 like they used to. "

Base Systems and the Arbitrariness of 100

Michael argues that 100's significance is entirely dependent on our base-10 counting system, making it arbitrary compared to 101's universal properties. He points out that in different base systems, 100 wouldn't hold the same special status, whereas 101's primality transcends numerical bases. The discussion explores how our decimal system is merely a product of having ten fingers, and base-12 would arguably be superior for everyday calculations.

  • The ease of calculating with 100 is purely because of the decimal system, not inherent mathematical truth
  • Base-12 would be superior because 12 is divisible by 2, 3, 4, and 6, unlike 10 which only divides by 2 and 5
  • 101 is prime in any base system, giving it universal mathematical significance
  • Understanding the arbitrariness of number systems helps children see math as a tool they can control
" If only we'd been born with two extra fingers. That's all it would have taken. And instead, we're stuck here in a world that is predominantly decimal based. "
" 101 is prime. By being prime, it transcends number systems. It can transcend cultures, but even species and even intelligences. "

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