Expressions are created by using the keys on the smartphone as well as selecting functions and constants from the phone's menu to build an expression in the Expression Text Box. The menu also has a selection for "Shortcuts" which will help make typing expressions easier. (Note: The menu items will only be visible when the cursor is in the Expression Text Box).

When finished, users simply select the "Enter" key and the expression will be evaluated. Previously created functions may be selected and edited from the Expression List.

There are two major types of expressions, Graph expressions and Arithmetic expressions.

When a graph expression is evaluated, a plot of the graph will be shown in the plot area at the top of the phone's display. Enter expressions directly from the phone keyboard or select the Menu key and "Functions..." to select from a shortcut list. For example:
y=sin(x)
y=x^2
y=(x^2-2x+4)/(x-2)

When arithmetic expressions are evaluated, the results are put into the Expression List. The following are examples of arithmetic expressions:

45+2+9

SQRT(3^2+4^2) (Extra points if you know what this represents!)

To activate Zooming and Scrolling, simply select the Toggle Zoom/Scroll menu item. When activated, clicking on the trackwheel will zoom in. If the ALT key is held down, clicking on the trackwheel will zoom out. Scrolling is done by rolling the trackwheel. To end Zooming and Scrolling, just select the Toggle Zoom/Scroll menu item again.

This feature assumes you have the ability to send email using your smartphone. To send the graph, just select the Share Graph via Email menu item. Provide a destination email address, optional notes, and just select the OK button! This feature can be used to print the graph, incorporate into a homework assignment or share with a classmate or teacher.

- Use common symbols for: + Addition, - Subtraction, * Multiplication, / Division, ^ exponent operator.

- Follows the standard order of operations taught in Algebra courses: Parentheses, Exponents, Multiplication and Division, Addition and Subtraction.

- Follows conventions for x and y variable definitions, for example, in the equation for a line:
y=mx + b
x represents the independent variable plotted on the horizontal axis/abscissa, and
y is the dependent variable plotted on the vertical axis/ordinate.

- Use of upper/lower case in expressions is arbitrary.

- Use of "y=" at the beginning of the expression is optional.

- Use of the * for multiplication is optional, for example, y=5*x+7 can be entered as y=5x+7.

- Enter equations directly into the text box labeled “Expr”

- Simple arithmetic expressions, e.g., 4+4 can be entered directly into the textbox

- Finish entering a function by pressing the enter key (key labeled with a down and left facing arrow).

- To start entering a graphed equation, press the Menu key and select “Start Graph Expression” from the pop-up box to add “y=” to the expression field.

- To clear the expression field, press the Menu key and select “Clear Field”

- To clear a graph, press the Menu key and select “Clear Graph”

- To add a common constant (for example, e or pi) to an expression, press the Menu key, select “Constants…” and select the desired constant

- To add a common function to the expression, press the Menu key, select “Functions…” and select the desired function from the drop down list

sin() - sine of a value or expression

cos() - cosine of a value or expression

tan() - tangent of a value or expression

arcsin() - arc cosine of a value or expression

arccos() - arc cosine of a value or expression

arctan() - arc tangent of a value or expression

x^2 - a value or expression raised to the second power

sqrt() - square root of a value or expression

ln(x) - natural logarithm of a value or expression

log(x,10) - logarithm base 10 of a value or expression

log(x,y) - logarithm base y of a value or expression x

pow(x,y) - a value or expression x raised to the power y

x! - returns the factorial for x, e.g., 3! = 3*2*1 = 6

abs() -absolute value of an expression

average(n1,n2,n3) - returns the average of n arguments

min(n1,n2,n3) - Returns the lesser of n arguments

max(n1,n2,n3) - Returns the greater of n arguments

floor() - Rounds values or expressions down to the nearest integer

ceiling() - Rounds values or expressions up to the nearest integer

pi - the constant, PI = 3.141592653589793...

e - the Euler constant, base for the natural logarithm, e = 2.718281828459045...