In this video there are 3 guys fighting over how many doughnuts each officer will get. There were 7 officers and 28 doughnuts. The doughnut maker's error was that he took the 28 doughnuts and 7 officers and instead of dividing to get four, he gave the two to a guy to hold. He put 7 into 8 one time and got the three by adding to 2 to the remainder (1). You can make this mistake by adding ANY two numbers together instead of dividing them correctly.