Is there a quick method to calculate the number of resonance structures for a given compound without drawing the Lewis structures? in MCQ's it will take a long time to find the answer if drawing Lewis structures are attempted.
i don't think that there's a shortcut but practice makes perfect. Draw, draw and draw again after drawing a lot; you'll be able to count similar structures without drawing all of them to the fine point.
Bumping the post so that seniors can see