Guess How Many Pumpkin Seeds Are in the Pumpkin! Date October 30, 2014Posted by sanderslibrary1550 Comments0 plain pumpkin before carving Yuck! Slimy seeds were slipping everywhere! washing and draining the seeds to get the gook off 50 piles of 10: 5 rows of 100 seeds + 10 more = 510 seeds. This student guessed that the pumpkin had 505 seeds. His guess came the closest to the actual number of seeds in the pumpkin: 510. He won the new Diary of a Wimpy Kid: The Long Haul as his prize!