? An old woman living on a pension in Chicago, USA, went home after minor surgery in the hospital. Two weeks later, she received a bill from the hospital, amounting to $63,440. When she saw such a huge number, she couldn't help being surprised. She had a heart attack and fell to the ground dead. Later, someone checked with the hospital. As a result, the computer misplaced the decimal point, and actually only needed to pay $63.44. A wrong decimal point actually killed a person. As Newton said, "In mathematics, the smallest error can't be ignored.