Swallowing gold by sleeve is a quick calculation method among the people and a numerical calculation method invented by ancient Qin Jin businessmen in China. The sleeves of ancient clothes were large, and only two hands were in the sleeves when calculating, so it was called swallowing gold in the sleeves. There used to be a ballad about this calculation method; "Swallowing gold on the sleeve is as wonderful as a fairy, and the number of fingers is moving. You learn priceless treasures, but your bosom friends don't pass them on."
Calculation method
The method of swallowing gold in the sleeve is to use five fingers of the left hand as a digital dial, each finger represents a number, and five fingers can represent five numbers: one, ten, hundred, thousand and ten thousand. The upper, middle and lower segments of each finger respectively represent the number 1-9. Arrange three numbers on each section, and the arrangement rules are divided into three columns: left, middle and right. Fingers are arranged upside down on the left (from bottom to top), 1, 2, 3; Fingers are arranged upside down (from top to bottom) in the middle, 4, 5, 6; Fingers are arranged upside down, 7, 8, 9. The calculation method of swallowing gold in the sleeve is a method of using mental arithmetic to reproduce the calculation process with the image of the brain and get the result. It regards the left hand as a five-gear abacus, and uses the right hand to count according to this abacus. When counting, point the fingers of your left hand with the fingers of your right hand. Its clear division of labor is: right thumb/left thumb, right index finger, left middle finger, right ring finger, left ring finger and right little finger. The corresponding professional division of labor does not interfere with each other. When the finger clicks on the number, it stretches out, and when it doesn't click on the number, it bends, indicating 0, so that four operations of addition, subtraction, multiplication and division of any number within100000 digits can be performed.