Math-related t-shirt idea?

<p>My high school's math honor society, is making shirts, in the style of a sports jersey. Where the number usually goes, we're supposed to pick a math symbol or equation that somehow means something funny or witty. The only catch is it has to fit where the number would go on the back. Any ideas?</p>

<p>ε < 0</p>

<p>10char</p>

<p>Not actually a joke but “my other calculator is a TI-Nspire”</p>

<p>π (or e)
We’re irrational.”</p>

<p>i
We’re unreal.”</p>

<p>Without math, I wouldn’t be able to function.</p>

<p>√-1 survived calc</p>