Please, don't post the answers, I'm sure some people will enjoy figuring it out by themselves :-)

1.

**1 = 2?**

a = b #multiply by b ab = b² #subtract a² ab - a² = b² - a² #factor a(b - a) = (b - a)(b + a) #divide by (b - a) a = a + b #since a = b, substitute a = a + a a = 2a #divide by a 1 = 2

2.

**0.99999... = 1?**

NOTE: 0.99999 is a repeating decimal that has infinite number of 9's.

1/3 = 0.33333.... #multiply both sides by 3 3/3 = 0.99999.... 1 = 0.99999....

3.

**1 + 1 = 0?**

This one is a bit more complicated, it uses an imaginary unit

*i*which defined as √ -1.

Note that

*i*x

*i*= -1

1 + 1 = 1 + √ 1 = 1 + √ (-1 x -1) = 1 + √ (-1) x √( -1) = 1 + i x i = 1 + -1 = 0

If you know other math tricks, please post them!