Re: [Math4u] Re: Math persons

A bunch of mails ago I already proposed a solution:
If there is even the slightest chance of confusion you haven't added
enough parentheses yet.

Seriously, there are two very different things:
- Rules how to evaluate any formula which is syntactically valid. Very
useful for computers, since they need to be able to handle everything
you throw at them. These rules have to be very exact. If you want to
know these exact rules, just go to mathworld or (if you want to check
you understood correctly) enter your formula in Google:

www.google.com/search?q=16+++%2F+++2%28+8+-+3%284++-++2%29%29++%2B1+%3D+

which'll tell you "((16 / 2) * (8 - (3 * (4 - 2)))) + 1 = 17".
- Rules / guidelines / common sense about how to write formulas in such
a way that other people can easily understand. Even if your formula
is technically correct (= computers always understand correctly) but
it confuses any human reading it (such as "16 / 2[1+1]" -> nice job
with the spaces, only adds to the confusion, how about "16/2 [1+1]"
or even "16/2 * [1+1]"?), then IMHO you did a bad job.
This way, you don't need complex rules, some simple rules (multiply-
before-add, parenthesis-first, that kind of thing) suffice.

Just my two cents,
Rob

-------- Original-Nachricht --------
> Datum: Tue, 4 Dec 2007 02:40:38 -0800 (PST)
> Von: Vinaire <vinaire@yahoo.com>
> An: Math4u@yahoogroups.com
> Betreff: Re: [Math4u] Re: Math persons

> What you are claiming is not obvious or agreed upon. That is why
> parenthesis are used to prevent ambiguity.
>
> For example, -2^3 is not the same as (-2)^3.
>
> I think that schools generally do a poor job of clarifying the use of
> parenthesis.
>
> Vinaire
>

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