Because in junior high school mathematics, there are many algebraic expressions containing unknowns, and the most common symbol of unknowns is "X", which is similar to the multiplication symbol (×), and it will be confused if you are not careful. So we use ""or direct ellipsis instead of multiplication sign (×).

In addition to the sign (), we generally use fractions (for example, 3 ÷ 4 =? )。 Because the mathematical calculation in junior high school is not limited to integers, but also rational numbers and irrational numbers (roots). Using the division symbol () will be troublesome, but using division and fractional line can greatly simplify the operation difficulty.

Therefore, get used to it one day earlier and relax one day earlier.