Maths Help Needed

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marinyork

Resting in suspended Animation
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Logopolis
cisamcgu said:
Perhaps (if I even knew what that meant) .. but, I thought my logic wasn't too bad. However, I acknowledge my less than deep understanding. Sorry

It's not that. It is just that it is the prefered way to express even numbers as the other way round to what you did, as a set of numbers 2k and 2k+1. It's just 3 ways of saying the same thing.

Two numbers are congruent modulo to each other if their difference is a integer multiple of n/same remainder when divided. In this case n=2. You get a set of even numbers that obey modular arithmetic with each other using 2 and a set of odd numbers too.

0 used to be fairly simple as a concept until about 100 years or so ago. Now there's a lot of baggage with it.
 

cisamcgu

Legendary Member
Location
Merseyside-ish
marinyork said:
It's not that. It is just that it is the prefered way to express even numbers as the other way round to what you did, as a set of numbers 2k and 2k+1. It's just 3 ways of saying the same thing.

Two numbers are congruent modulo to each other if their difference is a integer multiple of n/same remainder when divided. In this case n=2. You get a set of even numbers that obey modular arithmetic with each other using 2 and a set of odd numbers too.

0 used to be fairly simple as a concept until about 100 years or so ago. Now there's a lot of baggage with it.
OK .. I probably should understand this, but my brain is old :biggrin:
 

marinyork

Resting in suspended Animation
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Logopolis
Modular arithmetic is simple but not really used.

Say we take odd numbers.

3=1mod2. 3 -1 = 2k where in this case k=1
5=1mod2. 5-1 = 4 = 2k where in this case k=2
Also in the same set we have all sorts of combinations 5=3mod2, 19=17mod2 and whatever.

Similarly even numbers have a similar relation. However you cannot have 2=1mod2 or 4=3 mod2 or any kind of combinatation of odd and even mod2. You get two infinite sets. There's not even anything unique about numbers used in it, there are an infinite number of combinations using 1mod2.
 

marinyork

Resting in suspended Animation
Location
Logopolis
I believe modular arithmetic used to be taught in primary schools. It wasn't when I was but the lecturers who did the teaching of groups, set theory and foundations insisted it used to be. It's not completely unhelpful either if you're trying to teach school children about long division of numbers, chinese remainder theorem and various other things that have been in and out of the syllabus.
 
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