Change the formulae to text, then copy and paste then convert them all back to formulae.
To do this select the formulae, do Edit/Replace and change = to # and press Replace All. This changes all the formulae to text, so then do the copy and paste.
Select your copied text, and do Edit/Replace changing # to = pressing Replace All, and hey presto you now have formulae again. Remember to change back your source cells as well.