[Haskell-beginners] How to save a bracket in this case?

Hi, I want to calculate *(81/10)^2*. However, after I typed *81/10*, I remembered to add a bracket to surround *81/10*. Is there one way to do some trick to save this bracket? Actually I can *Ctrl+A* to move to the first character of this line. I want the other solution. Yi