Sunday, 21 February 2010

What is two divided by zero?

This question figured in a basic maths exam which 96% of primary teachers gave the wrong answer, the correct one being 'infinity'. Now this is obviously cobblers. But a letter to today's Observer claims that the right answer is 'there is no solution to this equation', and gives a persuasive argument to this effect - whatever you multiply or divide zero by, it remains zero.

I say double cobblers. The right answer is 'two'. 'Zero' is just notational shorthand for 'the absence of number', or 'nothing' if you prefer. 2 + nothing = 2. 2 x nothing = 2. I rest my case.

Any mathematicians out there?

8 comments :

  1. This is clearly a ghost of departed quantities. Thanks to George Berkeley.

    And if you get it wrong this can also cause big American ships to stop moving.

    http://en.wikipedia.org/wiki/Division_by_zero (historical accidents)

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  3. Sorry I really can't get the hang of this linking stuff. I think it should be
    http://en.wikipedia.org/wiki/Division_by_zero

    But it seems you can't test the link in the preview. Unless you know differently. In which case please tell.

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  4. The Wikipedia article makes my point very neatly, whilst reaching the opposite conclusion. Divide 10 apples amongst zero people - what are you left with? Ten apples, I humbly submit.

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  5. Nah, it's not that simple. You can't divide 10 apples amongst zero people because who is left with the 10 apples? If you are the apple-owner & want to give the apples away to no-one, then you are still the one left with them, not the no-one. You'd have to destroy the apples to divide them amongst no-one, so the answer is thus no apples (zero). If you keep them you have divided the apples amongst one person - you.

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  6. No it has to be infinity.
    What you forget is that maths is not logical. It's all in the mind of mathematicians.

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  7. And if someone steals them before you have a chance to give them away?

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  8. I like Rosie's idea best!! Anyway, is it important to the overall plan? I have got to the age where if I can't solve a puzzle within 10 minutes, I give up! Life is too short!

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