Two-digit multiplication algorithm:

1, two digits are aligned according to two digits, and ten digits are aligned according to ten digits.

2. Multiply each digit of another two-digit number with each digit of that two-digit number.

3. Multiply the ten digits of one two-digit number with each digit of another two-digit number, and the digits of the multiplication result should be aligned with the ten digits of the previous result.

4. Then add the two results to get the result of multiplying two digits by two digits.

On the calculation method of multiplication

1, the common method of using pencil and paper multiplier needs a very small number (usually any two numbers from 0 to 9) to store or query the product multiplication table, but a farmer multiplication algorithm does not need it.

Multiplying a number with multiple decimal places is troublesome and error-prone. The universal logarithm was invented to simplify this calculation. The slide rule allows numbers to be quickly multiplied by about three digits of precision. Since the early 20th century, mechanical calculators, such as Marchant, have automatically multiplied as many as 10 digits. Modern electronic computers and calculators greatly reduce the need for manual multiplication.