Format of the command is
name:=expression
Expression is assigned to variable, specified
by name without preliminary evaluation.
Variable and its value are displayed in Variable Zone. Name may
contain letters, digits and underscore, must begin with a letter and should not
exceed 7 characters.
Examples:
n:=5/2 ; assigns value 5/2 to variable n
x:=0 ; assigns value 0 to variable x
s:=cos(x) ; assigns value cos(x) to variable s
y:=s+n ; assigns value s+n to variable y