One of the biggest issues I find when trying to work with calculators in the class is having the basic settings right so that the calculator works properly. If there is a question of an error given by the calculator it is usually first a problem with a setting.
You should take a minute to familiarize yourself with how the basic settings of the calculator should be entered. This will save you a lot of grief when you get in the middle of the test and you just can't get the calculator to work!!!
One of the biggest culprits when the calculator just won't work right is when it is in the wrong mode settings. The mode effects the entire setup of the calculator and how it perceives the numbers and functions that are inputted. For normal operation the mode screen should look like below with one exception below that.The exception for this under normal operation would be if you are giving the calculator angles that would be in degree mode. In that case everything else should be the same but your mode school should look like below: