Multiplication has two meanings: 3×5 means the addition of five 3s, and 5×3 means the addition of three 5s. In multiplication representation, the factor after the multiplication sign is often taken as the multiple of the factor before the multiplication sign; Multiplication is not a simple symbol of addition.

If there is a direct ratio between the dependent variable f and the independent variable X 1, X2, X3, ... Xn are qualitatively different from each independent variable, without any independent variable f, it will lose its meaning, which is called multiplication.

Ancient multiplication:

Multiplication is one of the basic operations in mathematics. Suppose a times b equals c, which means ab=c or ab = C.

In ancient China, multiplication was carried out by several chips. There are three layers in calculating multiplication: the upper layer is the multiplicand, the middle layer is the product and the lower layer is the multiplier. Multiply the multiplicand by the largest bit of the multiplier, remove the calculation of this bit after multiplication, multiply it by the second bit, and add the numbers on the corresponding bits of the two products until the multiplication is over.

For example, 8 1 × 8 1, first put the multiplier and the multiplicand in the high position and the low position respectively. Multiply 80 by 8 1 to get 6480. When it's used up, it drops. 8 1 times 1 to get 8 1, plus 6480, it is equal to 656 1. When it's used up, it drops.