Share for share gain in business valuations

Hi, I am having problems understanding how to calculate gain/loss on acquisition for the target and bidding company's shareholders. I understand how to value to the company through the various valuation techniques in the syllabus but cannot work out the gain. This applies to questions where there are share for share exchanges (e.g. 3:2 shares). I have the Kaplan textbook but they don't really explain in much detail the best way to work this out. Are there any formulas that can work this out? Could I please have your help on this? Thanks