Sorting out the error-prone knowledge points of mathematics in grade three
The concepts of 1, rational number, irrational number and real number are misunderstood, and the concepts of reciprocal, reciprocal and absolute value are confused. I can't figure out the classification of absolute value and number. There are many multiple choice questions.
2. With regard to the operation of real numbers, the key to mastering the concepts and properties related to real numbers and flexibly applying various operation rules is the close symbol; In more complex operations, the order of operations is not paid attention to or the algorithm is used unreasonably, which leads to errors in operations.
3. The difference between square root, arithmetic square root and cubic root.
4. When the fractional value is zero, it is easy to ignore that the denominator cannot be zero.
5, decimal operation should pay attention to the change of algorithm and symbol. When the denominator of a fraction is a polynomial, factorization should be carried out first, and then factorization should be carried out until it can no longer be decomposed. Pay attention to the calculation method, you can't remove the denominator and turn the fraction into the simplest fraction. Filling in the blanks is easy to test.
Similar triangles Chang Jian Kao Dian
Test center: similar triangles's concept, the meaning of similarity ratio, and the enlargement and reduction of drawing graphics.
Assessment requirements: (1) Understand the concept of similarity; (2) Grasping the characteristics of similar figures and the significance of similarity ratio, we can enlarge and reduce the known figures as needed.
Test sites: the proportion theorem of parallel lines and the related theorem of parallel lines on one side of a triangle.
Examination requirements: Use the proportional theorem of parallel lines to understand and solve some geometric proofs and geometric calculations.
Note: An edge judged to be parallel cannot be used as the corresponding line segment in the condition in proportion.
Test site: similar triangles's concept
Evaluation requirements: Based on the concept of similar triangles, master the characteristics of similar triangles and understand the definition of similar triangles.
Inspection Center: similar triangles's Judgment, Nature and Application
Examination requirements: Master similar triangles's judgment theorem (including preliminary theorem, three judgment theorems, right triangle similarity judgment theorem) and its properties, and can apply it well.
Knowledge points of functions and formulas
Error-prone point 1: The concepts of rational number, irrational number and real number are misunderstood, and the meanings of reciprocal, reciprocal and absolute value are confused. And the classification of absolute value and quantity. Choose a compulsory exam every year.
Error-prone point 2: The key to real number operation is to master the concepts and properties related to real numbers and flexibly use various algorithms. In more complex operations, the order of operations is not paid attention to or the algorithm is used unreasonably, which leads to errors in operations.
Error-prone point 3: the difference between square root, arithmetic square root and cubic root. Fill in the blanks must be tested.
Error-prone point 4: When the score value is zero, students tend to ignore that the denominator cannot be zero.
Error-prone point 5: Pay attention to the change of algorithm and symbol when calculating the score. When the denominator of a fraction is a polynomial, factorization should be carried out first, and then factorization should be carried out until it can no longer be decomposed. Pay attention to the calculation method, you can't remove the denominator and turn the fraction into the simplest fraction. Fill in the blanks must be tested.
Error-prone point 6: the nature of non-negative numbers: the sum of several non-negative numbers is 0, and each formula is 0; Integral replacement method; A completely smooth road.
The above is what I sorted out for you. What are the key knowledge points summarized in the common test of junior three mathematics?