[onedoug]

#117: Though it took Bertrand Russell, in his Principia, some 400 pages to rigorously prove that 1+1=2.

[Aurelius]

"Though it took Bertrand Russell, in his Principia, some 400 pages to rigorously prove that 1+1=2."

I may be wrong, but I would doubt that "1 + 1 = 2" is a proposition in Principia Mathematica.