Under the seventh grade mathematics published by People's Education Press:

Intersecting line and parallel line, real number, plane rectangular coordinate system, binary linear equation, inequality and inequality group.

The part you asked should belong to the real part, square root, cube root and real number.

A positive number has two square roots, for example, the square root of 25 is 5, in which we call the square root of a positive number arithmetic.

Definition of square root: if x? =a, then x is the square root of a.

If 2? =4, 2 is the square root of 4, (-2)? =4, -2 is the square root of 4.

Definition of arithmetic square root: Is the positive square root of a non-negative number called its arithmetic square root?

For example, 2 and -2 are the square root of 4, and 2 is the arithmetic square root of 4.

Extended data:

If the square of a number is equal to a, then this number is called the square root of a, and A can be a specific number or an algebraic expression with letters.

Namely: if x? =a, then √ a is called the square root of a, and x = √ a. Where a is called the number of prescriptions. Where the positive square root is called the arithmetic square root.

Regarding the concept of quadratic radical, we should pay attention to:

The number of roots can be a number or an algebraic expression. If the root sign is a positive number or 0, its square root is a real number; If the root sign is negative, its square root is imaginary.