To guess a patent number, simply type the number of the patent you think applies. Thus, for example, if you think the invention was for the 1 millionth patent, enter the number 1. For the 5 millionth patent, enter the number 5, etc. If you are only off by 1 million patent numbers, you will be allowed to guess again. If you are off by more than 1 million patent numbers, your answer will be incorrect. It is strongly recommended that you read all the patent descriptions before answering.