First, the emphasis is different.
Primary school mathematics focuses on laying a good mathematical foundation, while junior high school mathematics focuses on cultivating students' mathematical ability, including calculation ability, self-study ability, problem analysis and problem solving ability, abstract logical thinking ability and so on.
Second, the difficulty of the content is different.
Junior high school mathematics has added complex knowledge of plane geometry, systematically studied algebra knowledge and solved practical problems by using equations; Number is extended to rational number and real number; There are simple linear functions and quadratic functions. The learning content of junior high school mathematics has increased and deepened, and the difficulty and requirements have increased.
Third, the amount of knowledge is different.
Junior high school mathematics knowledge increases, learning time is short and speed is fast. Learn some basic knowledge of mathematics in primary school for six years, and six books in junior high school for three years. In fact, you have to study for two and a half years, so you have to squeeze out half a year to review the senior high school entrance examination.
Extended data:
Equality relation commonly used in junior middle school mathematics
1. Travel problem (uniform motion) Basic relationship: S = vt (1) Meeting problem (simultaneous departure):+=;
(2) Catch-up problem (starting at the same time): If Party A starts t hours later, Party B will start and then catch up with Party A at B, then?
(3) sailing in the water:
2. batching problem: solute = solution × concentration solution = solute+solvent
3. The question of growth rate
4. Engineering problems: Basic relationship: workload = working efficiency × working time (workload is often considered as "1").
5. Geometric problems: Pythagorean theorem, area and volume formulas of geometric bodies, similar shapes and related proportional properties.
Pay attention to the relationship between language and analytical formula.
For example, "more", "less", "increase", "increase to (to)", "at the same time" and "expand to) ... Another example is a three-digit number, where A has hundreds, B has tens and C has tens, so this three-digit number is: 6544.
Pay attention to writing equal relations from language narration.
For example, if X is greater than Y by 3, then x-y=3 or x=y+3 or X-3 = Y, and if the difference between X and Y is 3, then x-y=3. Pay attention to unit conversion, such as "hours" and "minutes"; Consistency of s, v and t units, etc.
References:
Baidu encyclopedia-junior high school mathematics