![Section 1.3 - GEOCITIES.ws](http://s1.studyres.com/store/data/009588831_1-381c2df4d9847aca30e393906a5e2a53-300x300.png)
Introduction To Signed Numbers
... either positive or negative. A number line is a horizontal line that represents all numbers. ...
... either positive or negative. A number line is a horizontal line that represents all numbers. ...
On the Consistency and Correctness of School
... well described, are always open to different interpretations (Ehrenfeucht & Mostowski, 1956). This applies to the most basic concepts, such as number, quantity, and space. Thus each mathematical concept may be viewed in many different ways. And there is no unique, correct way of understanding it (Ma ...
... well described, are always open to different interpretations (Ehrenfeucht & Mostowski, 1956). This applies to the most basic concepts, such as number, quantity, and space. Thus each mathematical concept may be viewed in many different ways. And there is no unique, correct way of understanding it (Ma ...
Infinity
![](https://commons.wikimedia.org/wiki/Special:FilePath/Screenshot_Recursion_via_vlc.png?width=300)
Infinity (symbol: ∞) is an abstract concept describing something without any limit and is relevant in a number of fields, predominantly mathematics and physics.In mathematics, ""infinity"" is often treated as if it were a number (i.e., it counts or measures things: ""an infinite number of terms"") but it is not the same sort of number as natural or real numbers. In number systems incorporating infinitesimals, the reciprocal of an infinitesimal is an infinite number, i.e., a number greater than any real number; see 1/∞.Georg Cantor formalized many ideas related to infinity and infinite sets during the late 19th and early 20th centuries. In the theory he developed, there are infinite sets of different sizes (called cardinalities). For example, the set of integers is countably infinite, while the infinite set of real numbers is uncountable.