Knowledge Points of "Angle Understanding" in Senior Two Mathematics
First, understanding the angle.
1, characteristics of an angle: one vertex and two sides (straight)
2. The size of the angle is related to the size of both sides, and has nothing to do with the length of both sides.
3. The angle of painting:
(1) Fixed Vertex.
(2) Draw a straight line from this point.
(3) Draw another side (at right angles, aim at the drawn side with the right angle side and draw a line along the other right angle side).
Second, the classification of angles:
1, understanding right angles: the characteristics of right angles,
2. Know acute angle and obtuse angle: acute angle is less than right angle, and obtuse angle is greater than right angle.
3. You can judge the right angle, acute angle and obtuse angle with a triangular ruler: overlap the vertex of the right angle on the triangular ruler with the vertex of the compared angle, then overlap one side of the right angle on the triangular ruler with one side of the compared angle, and finally compare the other side of the right angle on the triangular ruler with the other side of the compared angle. This line is a right angle, the inside is an acute angle and the outside is an obtuse angle.
4. Draw right angles, acute angles and obtuse angles.
Knowledge points of mathematical length units in the second grade of primary school
concept
Meter: The standard unit of length in the international system of units is "meter", which is represented by the symbol "m".
Decimeter: dm is one of the metric units of length, and 1 decimeter is equivalent to one tenth of 1 meter.
Centimeter: unit of length, abbreviated as centimeter.
Millimeter: English abbreviation for mm
(1 cm = 10/0mm =0. 1 decimeter =0. 0 1 m =0。 0000 1 km)
Understand rice
(1) meter is a commonly used unit of length.
(2) When measuring the length of a long object, take "meter" as the unit.
(3) The meter is represented by the letter "m".
④ 1 m = 100 cm.
Cognitive centimeter
(1) cm is a commonly used unit of length.
(2) When measuring the length of a short object, take "cm" as the unit.
(3) The centimeter is represented by the letter "cm".
④ 1 m = 100 cm.
Cognitive line segment
Characteristics of line segments:
① The line segment is straight; ② The line segment has two endpoints; ③ Line segments can measure the length.
Draw a line segment
How to draw a line segment:
Starting from the "0" scale of the ruler, you need to draw a line segment a few centimeters long and draw it to a few centimeters of the ruler. Draw a line 2 cm shorter than 5 cm.
Knowledge points of mathematical division in the second volume of the second grade of primary school
1, division of knowledge points in the table:
(1) Understand the meaning of average score. A simple division is calculated according to the multiplication in the table.
(2) The quotient can be obtained by multiplication formula.
(3) According to the meaning of multiplication and division, solve some simple application problems of multiplication and division.
(4) Divider Divider = quotient divisor = divisor × quotient = dividend
2. Division: It is one of the four operations. The operation of finding the other factor by knowing the product of two factors and one of them is called division.
3. The nature of division
A number divided by several numbers in succession is equal to the product of this number divided by those numbers. This is the nature of division. Sometimes simple operations can be performed according to the nature of the division. Such as: 300÷25÷4=300÷(25×4)
4. Division formula
(1) frequency divider = quotient
(2) Dividend quotient = divisor
(3) divisor × quotient = dividend
5. Dividends
A number divided by another number in a division operation, such as 24÷8=3, where 24 is the dividend.
6. Divider: In the division formula, the number after the divisor is called the divisor.
Example: 8÷2=4, then 2 is the divisor. Eight is dividends. The divisor cannot be 0, otherwise it is meaningless.
7. Quotient: In a division formula, dividend/divisor = quotient+remainder, and then it is deduced that quotient × divisor+remainder = dividend.
8. Quanshang
When the number A is divided by the number B (non-zero), its quotient is called complete quotient. For example, 9÷3=3, and 3 is the complete quotient.
9. Incomplete quotient
If the number A is divided by the number B (non-zero), the quotient obtained is incomplete. For example: 10 ÷ 3 = 3... 1, where 3 is an incomplete quotient.
10, the relationship between dividend and quotient
Dividend is enlarged (reduced) by n times, and quotient is correspondingly enlarged (reduced) by n times.
The divisor is expanded (reduced) by n times, and the quotient is correspondingly reduced (expanded) by n times.
Summarize the knowledge points of second grade mathematics;
★ Sorting out the key knowledge of mathematics in the first volume of the second grade of primary school
★ The induction of mathematics knowledge points in the first volume of the second grade of primary school
★ Summary of mathematical knowledge points in the first volume of Senior Two.
★ Summary of second-grade mathematics knowledge points of Jiangsu Education Edition
★ Arrangement of conceptual knowledge points in the first volume of second grade mathematics
★ Second grade mathematics knowledge points
★ Knowledge points of the first volume of second-grade mathematics published by People's Education Press
★ Knowledge points in the second volume of second grade mathematics published by People's Education Press.
★ Mathematics knowledge points of senior one and senior two.
★ Summary of Knowledge Points in the Second Book of Grade Two Mathematics (2)