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Dr Yan tests out a mathematical equation that seems to prove that 2=1. Or does it? Try the equation at home and see if you can spot the 'trick'?

a=b

[multiply both sides by a]

a脳a = a脳b

[add a脳a to both sides]

a脳a + a脳a = a脳a + a脳b

[subtract 2脳a脳b from both sides]

a脳a + a脳a - 2脳a脳b = a脳a + a脳b - 2脳a脳b

[You can re-write this as following:]

2脳a脳a - 2脳a脳b = a脳a - a脳b

[This can then be represented as:]

2(a脳a - a脳b) = 1(a脳a - a脳b)

[Divide both sides by (a脳a - a脳b)]

2=1