In Maple you can give an expression a name so that you can refer to it
by the name later on. The following example shows how to define the expression
and denote it by the name p.
> p:= x^3-3*x^2+4;
Names can be longer than one letter, e.g. dist would be a valid name for an expression. In general, Maple statements must be terminated with a semicolon (;). The main exception is when you are using the on-line help, as described below. The ``:='' notation is becoming common in Mathematics and Computer Science; in English it means ``is defined to be''.
Maple understands common mathematical notation in defining
expressions, as shown in Table 
.
Table: Binary arithmetic operators
Note that Maple doesn't allow implied multiplication. The string 3x would be interpreted as the name `3x' and not as 3 times x!
Maple has many commands for manipulating expressions. For example the factor command finds the factors involving rational roots of a polynomial and prints out the (partially) factored result. The command for substituting one expression into another has the syntax
> subs(variable = value,expression);
where variable is a variable that appears in the expression
expression and value can be a number or an expression. The two
examples below demonstrate subtituting the number 1 and the expression
for x in the expression p we defined in the previous
example.
> subs(x=1,p);
> subs(x=t^2,p);
would result in the expression 
. For more commands
involving expressions, see the on-line help or the section on Maple
commands.