# The Naked Scientists Forum

### Author Topic: A confusion of concept in basic arithmethic  (Read 2099 times)

#### J Rahman

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##### A confusion of concept in basic arithmethic
« on: 16/10/2009 05:25:52 »
What does a=b~c=d mean? [The symbol ~ stands for 'not equal to'; sorry my comp does not have a 'not equal to' symbol]. What is the relation here between a and d? a=d or a~d? What I'm actually asking is, whether the symbol '=' or '~' when used multiple times in an expression or a series of expression, relate the two terms standing just before and after the symbol or does it relate the initial term (here, a) with the term just after the symbol? I'm a bit confused about the notations. Please help.

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##### A confusion of concept in basic arithmethic
« Reply #1 on: 16/10/2009 08:13:34 »
a~d

#### Nizzle

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##### A confusion of concept in basic arithmethic
« Reply #2 on: 16/10/2009 10:52:34 »
I always type 'is not equal to' as this: =/=

#### daveshorts

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##### A confusion of concept in basic arithmethic
« Reply #3 on: 16/10/2009 11:12:18 »
Obviously because they are next to one another
a=b
c=d
and
b≠c
because a=b and c=d we can also deduce
a≠d
a≠c
b≠d

(Your computer may not have a ≠ button but the forum does... if you click on preview you can insert symbols into your posts)

However I am not sure whether a≠b≠c means that a≠c
talking to my housemate who knows more of these things than I an equals sign is a binary operator and only applies to things either side of it so
a≠b≠c
does not imply that
a≠c

#### LeeE

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##### A confusion of concept in basic arithmethic
« Reply #4 on: 16/10/2009 17:00:05 »
By convention '~' generally means 'equivalent to' or 'approximately', depending on context.  If you start using it for not equal to you could end up confusing people.

If you can't use '' then '!=' is widely understood, where the '!' character means NOT in logical terms.

Other than that, I think that daveshorts has nailed the answer: '=' and '' are binary operators, and are of equal precedence.  As there are no brackets in a=b≠c=d, to indicate superior precedence or hierarchy, then they are all of equal precedence and should be treated as several simultaneous binary statements, not a single compound statement where one specific occurrence must be solved before the others.

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##### A confusion of concept in basic arithmethic
« Reply #4 on: 16/10/2009 17:00:05 »