use buttons like a calculator, or math expressions can be entered directly into the result area by clicking/tapping it and using a keyboard (the area has multiple lines for long expressions), then when ready press equals = button
order of operations: parentheses, exponents, multiplication or division, addition or subtraction, if same precedence (like * and /) then computed from left to right
find the longer 'golden ratio' length, enter: length/phi
determine the hypotenuse of a right triangle enter sqrt(first^2+second^2) add closing parenthesis
trigonometry, eg. cosine: cos(45 deg)
speed, eg. 90 km/h to m/s etc.