Addition and subtraction:

Multiplication:

Department:

Find the arithmetic square root:

Longitudinal formula refers to a longitudinal formula in the calculation process, which makes the calculation simple. Each transition number is changed by the last transition number, and then the single digits of the last transition number are multiplied by 2. If carry is needed, advance 1, then increase the unit number by ten digits, and so on, and add the new operand to the unit number.