3 ±ε × 7 ∓ε

Without using a calculator or even pen and paper–or even doing the arithmetic in your head–¿which is the larger product? of:

- 3.01 × 6.99
- 2.99 × 7.01

You know 3 × 7 = 21. But what happens if you gently place your finger on the teeter-totter?

Although this is “just arithmetic” and so doesn’t require a learnèd vocabulary of higher mathematics, it touches on a few “higher maths” topics:

- bilinearity being the way I would answer it “conceptually rather than computationally”
- wiggly numbers
- ± ε
- statistical robustness
- tensor product of modules
- isoperimetric inequality
@zentree @isomorphisms what’s all that math nonsense? It’s just an instance of an isoperimetric inequality.

— Messi is my Homeboy (@gappy3000)

July 13, 2014

I’ll leave the question/reasoning unanswered with a space for you to answer which is larger and why.

3±ε × 7∓ε = 21±¿?