Su Jiaoban Elementary School Grade Four Mathematical Triangle Knowledge Points
1, and the figure surrounded by three line segments (the endpoints of every two adjacent line segments are connected) is called a triangle.
Draw a vertical line from the vertex of the triangle to its opposite side. The line segment from the vertex to the vertical foot is called the height of the triangle, and this side is called the bottom of the triangle. This triangle is only three stories high.
3. The triangle is very stable.
4. The sum of any two sides of a triangle is greater than the third side.
5, Su Jiaoban fourth grade elementary school mathematics triangle knowledge points: A triangle with three acute angles is called an acute triangle.
6. A triangle with a right angle is called a right triangle.
7. A triangle with an obtuse angle is called an obtuse triangle.
8. Each triangle has at least two acute angles; Each triangle has at most 1 right angles; Each triangle has at most 1 obtuse angles.
9. A triangle with two equal sides is called an isosceles triangle.
10, a triangle with three equilateral sides is called an equilateral triangle, also called a regular triangle.
An equilateral triangle is a special isosceles triangle.
12, and the sum of the interior angles of the triangle is 180.
13, and the sum of the internal angles of the quadrilateral is 360.
14. Two identical triangles can be used to form a parallelogram.
15. Two identical right triangles can be combined into a parallelogram, a rectangle and a big triangle.
16. Two identical isosceles right triangles can be combined into a parallelogram and a square. Large isosceles right triangle.
Summary of knowledge points in the first volume of fourth grade mathematics: count
Knowledge points:
Hundreds of millions of reading methods.
You must first read the numbers of 10, 1 0,000 and1100 million, then10,000, and finally 100. (that is, reading from a high position) Numbers of 100 million or 10,000 levels are all read by individual levels, followed by 100 million or 10,000. The zero at the end of the stage is not read, and the zero in the middle of the stage must be read. No matter how many zeros there are in the middle, read only one zero.
How to write numbers within 100 million.
Write from the top in numerical order. If there is no one in the middle or at the end, write 0 on that one.
Methods of comparing numbers.
Multi-digit comparison size, if the number of digits is different, then the number of digits is large and the number of digits is small. If the digits are the same, start with the first digit from the left, which number is larger and which number is larger. If the first digit from the left is the same, start to compare with the second digit … until the size comparison is finished.
Land area (multi-digit rewriting)
Knowledge points:
The method of rewriting numbers in units of "ten thousand" or "hundred million".
Taking "ten thousand" as the unit, the four zeros at the end must be removed and ten thousand words should be added; With "100 million" as the unit, the last eight zeros must be removed and hundreds of millions of words added.
The meaning of rewriting.
In order to facilitate reading and writing.
Forest area (approximate figure)
Knowledge points:
Characteristics of exact numbers and divisors.
The exact number is generally in the unit of "one", and the approximate number is in the unit of "ten thousand" or "one hundred million", and the mantissa is omitted.
The method of keeping approximate values by rounding.
Look at the next number to be reserved according to the requirements in the question. If this number exceeds 5, proceed to the previous number. If it is less than 5, give it up. Regardless of the last few digits of the mantissa. If it is accurate to 10 thousand digits, only a few thousand can be seen, and if it is accurate to 100 million digits, only tens of millions can be seen. Finally, be sure to write the name of the company.
Mathematics in the fourth grade of primary school, the first volume, the second chapter, summary of knowledge points
1, the understanding of large numbers must be divided into four places.
Grades, Numbers and Counting Units (tables are important) distinguish between counting units and numbers.
How to read large numbers (the key is how to read zeros)
How to write large numbers
Expand the number to three orders of magnitude
2. Rounding method
It is estimated that two digits are rounded to the nearest ten, three digits to the nearest hundred and four digits to the nearest thousand. I guess I saw the calculation symbol clearly. Especially similar to 1500-500/50, some people will calculate the subtraction first.
Rounding method
The application problems involved here include the method of ending and the method of entering one.
10 people take a car, and every four people have a car. How many cars does a * * * need? Furthermore, the remaining two people need a car.
60 kilograms of water per barrel, how many barrels of water can a truck with a load of 2 tons hold at most? Tailing method, the remaining 20 kilograms can't hold a bucket of 60 kilograms of water.
3. Area unit
Square kilometer (square kilometer), square meter, square decimeter, square centimeter, square millimeter.
Combined length unit
Check perimeter and area
It is necessary to combine the reality and let the children have an idea of the basic length and area.
4. Unit right
Grams, kilograms and tons
5. unit of volume
ML, liter
The difficulty of this chapter lies in: realizing the quantity and conversion of quantity units in combination with reality.
Units should be unified
Perimeter and area
In fact, the most important thing is to determine the length and width (a square is the side length)
1, rectangle
Area = length. width
Perimeter =2. (Length+Width)
We already know the area and length (or width) and find the perimeter or the other side.
Length = area: width
(width = area/length)
Perimeter =2 (length+area/length) =2 (width+area/width)
We already know the length (or width) of a week. Find the area or the other side.
Length = circumference /2- width
Width = circumference /2- length
Area = length. (circumference /2 times length)
= width. (circumference /2 times width)
2. Square
Area = square of side length
Perimeter =4. length of a side
Side length = square root of area (the square number that appears now is generally small, which can be calculated by multiplication formula table)
Side length = perimeter /4
Unit of length and unit of area
1 km =1000m
1M = 10DM = 100cm
1DM= 10CM
1 cm =10mm
1 km2 = 1 km2 = 1000000 m2
1 m2 = 100 square decimeter = 10000 square centimeter = 100000 square millimeter.
When the sum of two numbers is constant, when the difference is minimum or equal, the product.
That is to say, the area of a rectangle and a square with equal perimeter (the smaller the difference between the length and width of a rectangle, the larger the area), when the product of two numbers is constant, when the difference is, and.
That is to say, a rectangle and a square have the same area, and the circumference of the rectangle (the greater the length-width difference of the rectangle, the greater the circumference).
Summarize and sort out the relevant articles about the knowledge points of mathematics in grade four;
★ Summarize the knowledge points of the first volume of mathematics in the fourth grade of primary school.
★ Summarize the knowledge points of fourth grade mathematics.
★ Summarize the knowledge points of the fourth grade mathematical triangle.
★ Review materials of mathematics knowledge points in the second volume of the fourth grade of primary school.
★ Guidance of mathematics learning methods in the fourth grade of primary school
★ Knowledge points in the first volume of fourth grade mathematics
★ Summary of knowledge points in the second volume of fourth grade mathematics
★ Summary of Mathematics Learning Methods in Grade Four of Primary School
★ Summary of knowledge points for final review of fourth grade mathematics in Jiangsu Education Edition