For mathematics, x is used for cross multiplication, but it also needs to be divided into different situations. For example, "x" must be used between numbers, but electricity can be used in the equation, for example, 5.x stands for 5× x. Or the multiplication symbol such as 5x is omitted, which also stands for 5xx.

Point multiplication and cross multiplication (that is, point multiplication and x) are essentially the same in the multiplication operation of general real numbers and letters, and both represent the product relationship between numbers. However, some writing methods are stipulated, such as: only cross multiplication (2×3) can be used between numbers, and dot multiplication cannot be used (to avoid being regarded as decimal point).

In junior high school mathematics, when using the number product to represent the letter product relationship, the usage of multiplication symbols × and × is used to indicate whether the letter product relationship can be omitted.