1, with vertical columns, is mantissa alignment of factors.

2. When the column is vertical, for the convenience of calculation, factors with more digits are generally put on it.

3. If there are integer 10000 factors, the first digits of the two factors from the right are non-zero-aligned, and then the corresponding number of zeros is filled in the number.

If there is 0 at the end of the number, count the decimal point first, and then go to 0.

5. If there are not enough decimal places, you need to add 0 in front.

Extended data:

Multiplication law: multiplication satisfaction of integers: commutative law, associative law,? Law of distribution, law of elimination.

With the development of mathematics, the object of operation has developed from integer to more general group. Intra-group multiplication is no longer needed to satisfy the commutative law. The most famous noncommutative example is the quaternion group discovered by Hamilton. But the law of association is still satisfied.

1, multiplication commutation law:

Note: the letter is multiplied by the letter, and the multiplication sign need not be written.

2, the law of multiplication and association:

3, the law of multiplication and distribution:

References:

Baidu encyclopedia-multiplication