This riddle has been around for some time on internet platforms such as Instagram, Facebook, and WhatsApp, and many people still argue over what the answer might be, as there are many possibilities. The correct answer is When the first servant comes in, the king should write down his number. For each other servant that reports in, the king should add that servant’s number to the current number written on the paper, and then write this new number on the paper. Let x be the number of the missing servant and y be the number that the king has written. Once the final servant has reported in, the number on the paper should equal: y = (1 + 2 + 3 + … + 99 + 100) – x (1 + 2 + 3 + … + 99 + 100) = 5050, so we can rephrase this to say that the number on the paper should equal: y = 5050 – x So to figure out the missing servant’s number, the king simply needs to subtract the number written on his paper from 5050: 5050 – y = x