First, expand the information.
Absolute value is the distance from a point corresponding to a number on the exponential axis to the origin, and |b-a| or |a-b| represents the distance between a point representing a and a point representing b on the number axis.
In mathematics, the absolute value or the modulus |x| is non-negative, regardless of its sign, that is |x|=x means positive x, |x|=-x means negative x (in this case -x is positive), and |0|=0. For example, the absolute value of 3 is 3, and the absolute value of -3 is also 3. The absolute value of a number can be considered as the distance from zero.
The generalization of absolute value of real number appears in various mathematical settings, such as complex number, quaternion, ordered ring, field and vector space to define absolute value. Absolute value is closely related to concepts such as size, distance and norm in various mathematical and physical environments.
Second, how to learn junior high school mathematics well
1. Strengthen reflection after doing the questions.
Students must make it clear that the topic they are sitting on is definitely not the topic of the exam. But to use ideas and methods to solve the problems we are doing now.
Therefore, we should reflect on every question we have done. Sum up your gains. To sum up, this is a question of what content and how to use it. Make knowledge into pieces, problems into strings, accumulate over time, and build a scientific network content and method system.
2. Wrong title
Speaking of wrong books, many students feel that they have a good memory and can remember them without wrong books. This is an "illusion", and everyone has this feeling. When the problems increase and the learning content deepens, you will find yourself at a loss.
Wrong questions can record your own knowledge shortcomings at any time, which is helpful to strengthen the knowledge system and improve learning efficiency. Many schoolmasters got high marks because they used the wrong textbooks on their own initiative.
3 lay a solid foundation and learn to think
Basic scores account for the most in mathematics examination questions. Therefore, in the review teaching of junior high school mathematics, it is necessary to lay a solid foundation so that every student can meet the requirements of "understanding" and "mastering" junior high school mathematics knowledge. Apply basic knowledge skillfully, correctly and quickly.