1 + 1 = 2

[pythagorean]

Why it took 379 pages to prove 1+1=2



Three Dog Night - One (1969)



The Logical Song

[Bucky Ball]

2.4 + 2.4 = 4.8, or when rounded, 2 + 2 = 5.

[polymath257]

Axioms:
For all x, x+0=x
For all x,y, x+s(y)=s(x+y)

Definitions:
1=s(0), 2=s(1), 3=s(2), 4=s(3)

Then
1+1= 1+s(0)
=s(1+0)
=s(1)
=2

Also,
2+2=2+s(1)
=s(2+1)
=s(2+s(0))
=s(s(2+0))
=s(s(2))
=s(3)
=4

[airportkid]

Start with an identity:

A = B

Multiply both sides by B

A X B   =   B^2


Subtract A^2 from both sides

A X B  -  A^2  =   B^2  -  A^2


Factor

A X (B  -  A)   =  (B + A)  X  (B  -  A)


Simplify

A   =   B  +   A


Substitute A for B since A = B

A   =   A  +  A


OR

1  =  2

QED