"Professor Snellings proved that 1 = 2 as an example of how folks can manipulate statistics..."

Although I never learned from Professor Snellings, I believe that proof was algebraic:

The Proof that 2 = 1

1) a = b
1) Given

2) a2 = ab
2) Multiply both sides by a

3) a2-b2 = ab-b2
3) Subtract b2 from both sides

4) (a+b)(a-b) = b(a-b)
4) Factor both sides

5) (a+b) = b
5) Divide both sides by (a-b)

6) a+a = a
6) Substitute a for b

7) 2a = a
7) Addition

8) 2 = 1
8) Divide both sides by a

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Solution:

Part one: Step five is wrong. The rules of mathematics do not allow us to divide by zero.

Since a and b are equal, (a-b) = 0. Therefore, we cannot divide by (a-b)!