To simplify an algebraic expression, you should select one of the tabs for 'Simplify', 'Expand' or 'Factor'. Next, type in the problem as if you were typing it into an email. For exponents, either use the provided symbol for exponent or type it in directly using the '^' symbol (Shift+6), as in "x^2" [x-squared] or "x^3" [x-cubed].

The image shown below should make this clear. For more entry details, click the '?' question mark symbol shown to the right of the category tabs (Solve, Simplify, Factor, etc.).