Decimal multiplication
The calculation method of is: first, according to the calculation method of integer multiplication, after obtaining the product, look at how many decimal places there are in the two factors * * *, and then count several decimal places from right to left in the multiplied product.
The calculation method of fractional division is: first, make the divisor into an integer according to the invariant property of quotient, and then carry out it according to the calculation method of integer division, but pay attention to that the decimal point of quotient should be aligned with that of dividend.