USING MATHEMATICAL CONVENTIONS

Recall:
[beautiful math coming... please be patient] $\mathbb{R}\,$ is the set of real numbers:   [beautiful math coming... please be patient] $\mathbb{R} = (-\infty,\infty)$
[beautiful math coming... please be patient] $\mathbb{Z}\,$ is the set of integers:   [beautiful math coming... please be patient] $\mathbb{Z} = \{\ldots,-3,-2,-1,0,1,2,3,\ldots\}$

Numbers are usually represented by lowercase letters, like [beautiful math coming... please be patient] $\,a\,$, $\,n\,$, or $\,x\,$.
Sets are usually represented by uppercase letters, like [beautiful math coming... please be patient] $\,A\,$, $\,B\,$, or $\,S\,$.

A variable with universal set [beautiful math coming... please be patient] $\mathbb{R}\,$ (or, any interval of real numbers)
is most likely to be named with a lowercase letter from the end of the alphabet;
particularly [beautiful math coming... please be patient] $\,t\,$, $\,x\,$, or $\,y\,$.

A variable with universal set [beautiful math coming... please be patient] $\mathbb{Z}\,$ (or, any subset of the integers)
is most likely to be named with a lowercase letter near the middle of the alphabet;
particularly [beautiful math coming... please be patient] $\,i\,$, $\,j\,$, $\,k\,$, $\,m\,$, or $\,n\,$.

EXAMPLES:
Question: What is the best variable to represent a number, with universal set [beautiful math coming... please be patient] $\mathbb{R}\,$?
Choices: [beautiful math coming... please be patient] $\,x\,$, $\,j\,$, or $\,S$
Answer: [beautiful math coming... please be patient] $x$
Question: What is the best variable to represent a member of the set [beautiful math coming... please be patient] $\,[-1,3)\,$?
Choices: [beautiful math coming... please be patient] $\,B\,$, $\,k\,$, or $\,t$
(You may want to review interval notation.)
Answer: [beautiful math coming... please be patient] $t$
Question: What is the best variable to represent a set ?
Choices: [beautiful math coming... please be patient] $\,t\,$, $\,A\,$, or $\,m$
Answer: [beautiful math coming... please be patient] $A$
Question: What is the best variable to represent a member of the set [beautiful math coming... please be patient] $\{3,4,5,\ldots\}\,$?
Choices: [beautiful math coming... please be patient] $\,k\,$, $\,S\,$, or $\,y$
(You may want to review list notation.)
Answer: [beautiful math coming... please be patient] $k$
Master the ideas from this section
by practicing the exercise at the bottom of this page.

When you're done practicing, move on to:
‘Undoing’ a Sequence of Operations

 
 
What is the best variable to represent $\ldots$
 
 
 
    
(MAX is 13; there are 13 different problem types)