Deleting a Character or Function
Example: To correct the expression 369 ⋅ ⋅ 12 so it becomes 369 ⋅ 12
LINE Insert Mode:
369**12 
dd 
Y 
Overwrite Mode:
369**12 
ddd 
Y 
Correcting a Calculation
Example: To correct cos(60) so it becomes sin(60)
LINE Insert Mode:
c60) 
dddY 
s 
Overwrite Mode:
c60) 
dddd 
s 
Inserting Input into a Calculation
Always use the insert mode for this operation. Use d or e to move the cursor to the location where you want to insert new input, and then input what you want.