Keyboard description: A . Numbers, decimal points and positive and negative symbolic keys B. Cursor keys up and down or triangle function keys in calculator around
C . Confirmation key or "=" equal sign key in calculator
D . SDM coordinate system switching key or inverse trigonometric function switching key in calculator E . Relative or Absolute Coordinate System switching Key
F . metric or British switch key
G . coordinate value midpoint key
H . Functional Reuse Keys
I . Number Axis Display Value Zero key
J . axis selection key, used in setting up of center, setting and system, etc.
K . LCD Display Area, Display Axis Value, Current System Status and Multiplexing Functions