Using the basic calculator keys

0, 1, 2, 3, 4, 5, 6, 7, 8, 9

Enters numerals 0 through 9.

+, -, x, ÷

Adds, subtracts, multiplies, divides.

.

Inserts a decimal point.

±

Switches between the positive and negative sign for a value.

=

Completes all operations. (Available if RPN is not selected in the View menu.)

enter

Pushes the displayed value onto the calculator's stack. (Available if RPN is selected in the View menu.)

C

Clears display window. (Press the Delete key on your computer's keyboard to clear only the last digit entered.)

M+

Click after a calculation to add the displayed result to the value in memory. (M appears on the screen when memory contains a value other than zero.)

M-

Click after a calculation to subtract the displayed result from the value in memory. (M appears on the screen when memory contains a value other than zero.)

MR

Recalls the value from memory for use in a calculation.

MC

Clears the value in memory.

Exchange Registers
(labeled "x <‑> y")

Swaps the bottom two numbers on the RPN stack. (Available if RPN is selected in the View menu.)

Roll Up, Roll Down
(labeled "R‑Up Arrow", "R‑Down Arrow")

Moves the most recently entered number up or down the RPN stack. (Available if RPN is selected in the View menu.)

drop

Removes the bottom number from the RPN stack. (Available if RPN is selected in the View menu.)