Re: Math Puzzle

[_vince]

Quite silly, you are subtracting the number from a slightly modified version of that number, intuitive that it could cancel out, hardly a trick. I guess the 'trick' is sticking a bunch of 2's in there that cancel out to hide the fact that you're doing a mere addition to the original number

((x + 5)*2 - 2)/2 - x = ((x + 5) - 1) - x = x + 4 - x = 4

[_vince]

That makes it a little clever, hides the cancellation. The general form is

((x + a)*k - k*b)/k - x = a - b

so long as the number 'to subtract' is in the form k*b, you will always get the number a - b. I was wondering what goddamn show would try to pull this off but turns out it's a kid's math show so fair enough

[Ashish]

I used to do this trick to kids.. They are really amazed at this, and I told them that, "I have read your mind".