Search All of the Math Forum:
Views expressed in these public forums are not endorsed by
NCTM or The Math Forum.


Math Forum
»
Discussions
»
sci.math.*
»
sci.math
Notice: We are no longer accepting new posts, but the forums will continue to be readable.
Topic:
How do you prove that 2+2=4? Is it enough to consider 2 objects, then 2 more then put them together and count them and get 4, or do you have to resort to fancyschmancy methods?
Replies:
8
Last Post:
Nov 18, 2012 7:45 PM




Re: How do you prove that 2+2=4? Is it enough to consider 2 objects, then 2 more then put them together and count them and get 4, or do you have to resort to fancyschmancy methods?
Posted:
Nov 16, 2012 12:33 AM


In article <17eeb6262a354177ad6892cf18be577b@c16g2000yqe.googlegroups.com>, CharlieBoo <shymathguy@gmail.com> wrote:
> On Nov 15, 11:22 pm, donstockba...@hotmail.com wrote: > > Just askin. > > Principia Mathematica BS says it takes 100 pages. I don't know > anybody who has tried to explain what is going on there (everyone just > sits in awe at the number of pages), but Peano Arithmetic proves it in > a few steps where 2 is 0'' and 4 is 0'''', based on the axioms x+0=x > and x+y' = (x+y)' where x' is x+1 ("successor of x"). > > CB
You can view "Prinicpia Mathematica" at the link:
http://archive.org/stream/PrincipiaMathematicaVolumeI/WhiteheadRussellPr incipiaMathematicaVolumeI#page/n95/mode/2up
More is being done than just proving that "2+2=4". For example, logical propositions like "q implies (p implies q)" are being proved.



