(1) number alignment. Starting from the right, multiply the first factor by the number on each bit of the second factor, and the end of the number will be aligned with which bit of the second factor.

(2) Then add up the numbers multiplied several times.

(Multiply with 0 at the end of an integer: you can multiply the number before 0 first, then see how many zeros are at the end of each factor, and add a few zeros at the end of the multiplied number. )

Calculation rules of multiplication:

1, the first digit is the same, and the sum of the two mantissas is equal to 10. Multiplication method of two-digit numbers: add 1 to ten digits, and the sum obtained is multiplied by ten digits, and the number multiplied by one digit is the last product, and there is no ten digits to make up 0.

2. Multiplication method of mantissa with the same mantissa and two-digit numbers not equal to 10: Multiply two mantissas (i.e. the square of the mantissa) to get the front product, multiply the sum of the two mantissas by the mantissa to get the middle product, and multiply the two mantissas to get the back product.

3. Multiplication method: the first digit of the multiplier is added with 10, and the obtained sum is multiplied by the first digit of the multiplicand, and the obtained number is the front product. When the two mantissas are multiplied, the obtained number is the back product, and no ten digits are added with 0.

4. The sum of the first and last multiplicand is 10, and the multiplication method of two digits with the multiplier is similar to Help 6. The product of the first two digits plus the single digits of the multiplier, the number is taken as the front product, the two mantissas are multiplied, the number is taken as the back product, and no ten digits are supplemented by 0.