Two chemists walk into a bar.

The first says, “I’d like to order some H20.”

The second says, “I’d like to order some H20, too.”

The second man dies.

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An infinite number of mathematicians walk into a bar.

The first orders a beer.

The second orders half a beer.

The third orders a quarter of a beer.

The fourth begins to order, but, before he does, the bartender cuts him off, puts two beers on the bar and says, “you guys need to know your limits.”