The overall rating of a review is different from a simple average of all individual ratings.

Share this review on

Hi, dear Community!

Today I want to talk with you about set theory and describe roughly about "N - set of the natural numbers".

This theme best fits into the category "Everything that starts with N". Those of you who hate Mathematics should quickly click further.

1) What a kind of set is "N"? *****************************

The set contains any natural, positive numbers which are integral. "N" is the only set that has a starting point. This is what is called: numerable. Some mathematicians start at Zero, some at one. The following is therefore valid: "N" = Start at 1; N0 = Start at 0.

"N" is pretty restricted for calculating because only integral positive values are part of "N". That is why this set is hardly used.

2) How exactly look numbers which are part of "N"? ******************************************************

1, 1000, 1,0000000 (only zeros), 56

Only integral numbers which are greater or at most zero belong to "N" or decimal numbers which only have zero after the comma.

3) Which numbers are not parts of "N"? ******************************************

Negative numerical values, fractions, real numbers or complex values do not belong to "N".

Here are examples by using two equations:

a) 3 x + 5 = 20 | - 5

3 x = 15 | : 3

x = 5

5 is a part of "N". So a solution is given.

b) 3 x - 5 = -20 | + 5

3 x = -15

x = -5

Okay, the number is an integral value but negative and as a matter of fact this equation can not be solved in "N".

4) Result and my opinion: --------------------------------------

Summarised I can say that "N" is just good for additions with positive, integral numbers. The set is insufficient for other operations. Therefore "N" is pretty unnecessary.

How do I best rate "N"? The set is really not useful but at least the only one with a starting point. So I rate with 1 star and say: "N" = not helpful.

I thought your decision to review natural numbers was odd and unfair. You know there's a lot of maths out there than suggested here which makes use of the set of natural numbers. In the second part, the review should read, "Only integer numbers...".

Chouchinciao 29.09.2006 16:58

Um, is all I can find to say. Have to confess I got a bit lost. Does it have any use then?

Claiiiree 28.09.2006 02:00

don't know what you are going on about, in the context of a review, and I *am* very educated where maths is concerned..