Signal gating in full adder

Hi there,
Signal gating is a way in which switching activities is reduced. But how it is implemented for full adder. Please provide info. Or any links will be appreciated. Thanks in advance.

We need more info manuv.

'gating' springs to mind frequency counter circuits where you gate the amount of time a counter counts for, however I havent a clue what your adder has to do with it.