Are there any tricks (control or alt + something for example) to locking or
unlocking (probably not using the correct terms) of cell references in a
formula in order to set it up for the autofill scenario I want to do? For
example if I have the following formula:

=a1+b1

How can I easily change it to =$a$1+$b$1
or =a$1+b$1
or =$a1+$b1

I may just be crazy, but if you have any quicker command button suggestions
to change these scenarios easier than having to type them every time that
would be great. Thank you.
--
David P.