This is a simple classic calculator. Here are some key functions explained:

mc: erases the memory content
mr: gets the memory content
ms: stores the number on the display to the memory
m+: takes the number on the display, adds it to the memory and puts the result into the memory
m-: subtract the number in the display from the current number in the memory
<=: removes the last digit on the display
ce: resets the calculator and the memory
c: resets the calculator (but not the memory)
+/-: change the mathematical sign of
v: square root of
/: divide
%: calculate percentage => To calculate x percent of y simply enter x%y
*: multiply
1/x: a multiplicative inverse or reciprocal for a number x
-: subtract
+: add