Mathematics knowledge points in the first volume of the second grade of primary school

1. A ruler is a tool for measuring the length of an object. Commonly used length units are: meters and centimeters. The index finger is about 1 cm wide and the arms are about 1 m. 1m = 100cm 100cm = 1m。

2. The measurement unit of shorter objects is usually centimeters, and the measurement unit of longer objects is usually meters.

3. When measuring the length of the object: aim the "0" scale of the ruler at the left end of the object, and then see how many centimeters the right end faces the scale. Object length = large number-decimal number, for example, from scale "0" to scale "6" is 6 cm (6-0=6), and from scale "6" to scale "9" is 3 cm (9-6 = 3); You can also calculate the length of an object by counting.

4. The line segment is straight and its length can be measured.

5. Method of drawing line segments: Draw from the "0" scale of the ruler, the longer the better. (find some lines; Sometimes you have to work out the length before drawing a line. Draw a line 2 cm shorter than 6 cm. )

6. This angle has 1 vertices and two straight sides. Acute angle is less than right angle, obtuse angle is greater than right angle, and obtuse angle is greater than acute angle. Acute angle).

7. You can draw a right angle with a triangle, and the right angle should be marked with a right angle symbol (also called the vertical foot symbol).

8. All right angles are the same size. To know whether an angle is a right angle, you can compare it with the right angle on a triangle. A rectangle and a square have four corners, all of which are right angles.

9. The angle has nothing to do with the length of both sides, but with the size of both sides.

10, each triangle has three angles, of which 1 is a right angle and the other two are acute angles.

1 1, Angle drawing: Starting from one point, draw two straight lines in different directions with a ruler to draw an angle. A figure composed of two rays drawn from a point is called an angle. )

Mathematics learning skills

The purpose of education is not only to stay in grades, but also to cultivate learning methods and habits and cultivate thinking and interest. As a liberal arts student, if you want to get high marks in the college entrance examination, you must master the learning methods and draw inferences from others in peacetime.

I am well aware of the importance of mathematics to me. In my opinion, I must realize the importance of mathematics in peacetime. This is the beginning of a good attitude. If I look at mathematics correctly, I will not be too anxious, nor will I despise carelessness. If I face every exam with a more cautious and philosophical attitude, I will succeed.

A good attitude comes from the usual accumulation. If you take every small exam seriously, you will feel better and better in the excitement brought by moderate tension, which is one of the prerequisites for the success of the college entrance examination.