Elementary school mathematics concept
Date, year and month
135780 wax (65438+February),
Thirty-one days is never bad;
April 30th (165438+1October);
February 28th in a normal year,
Add one in February of leap year.
/kloc-prime formula within 0/00
2,3,5,7 and 1 1,
13 is followed by 17.
19, 23, 29, ( 19, 23, 29)
3 1, 37,41,(Sany, Sanqi, Forty-one)
43, 47, 53, (43, 47, 53)
59, 6 1, 67, (59, 6 1, 67)
7 1, 73, 79, (7 1, 73, 79)
83、89、97。 (83, 89, 97)
Reading French songs with multiple digits
Reading should start from a high position, and whoever reads it will read it.
If there is a zero at the end of each stage, you don't have to read it out.
If the other numbers are zero in a row, just read one.
Read 10,000 at the end of 10,000 and 100 million at the end of 100 million.
Multi-digit song writing
Write a few numbers from it, as many as you want.
Whoever doesn't have a unit, remember to use 0 to occupy the place.
Multi-digit size comparison song
The number of digits is different from the size, and the number of digits is more than the number of digits.
The number of digits is the same, but there are fewer digits and more digits.
Operation sequence song
Playing bamboo boards rang all over the sky. Listen to me, students
Today we will talk about four operations instead of other tables.
Clear order is the key to the calculation of mixed test questions.
The operation at the same level is the best, and it is calculated from left to right in turn.
There are two levels of operations, first multiplication and division, then addition and subtraction.
What should I do if I encounter parentheses? Parentheses take precedence.
After parentheses, the order cannot be out of order.
Check every step, and be happy when you are right.
The meaning of "fen"
See "division",
Circle,
The word "divide" is preceded by a divisor,
The dividend aft that word "divide",
Switch places. Don't forget.
Division with zero in the middle or end of quotient.
I'm 0, I'm good at it,
Organization works miracles.
Not enough quotient 1, I'll make up,
I will sit when there is a vacancy.
If someone wants to get rid of me,
I always win.
Know the clock
The fastest runner is the second hand, tall and in good shape;
The slowest runner is the hour hand, short and fat.
Not high or short is the minute hand, and running at a constant speed is very effective.
Measuring angle
Center to apex,
0 line to one side,
When reading the scale,
Distinguish between inside and outside.
Conversion between measurement units
Make it bigger and smaller. Make good use of it.
Small and big, not bad.
Memories of the big moon and the small moon
Seven months ago, when I was one month old,
Eight months later, two months later.
I am 1 cm.
1 cm, very naughty, look carefully before I see you,
Nail cover 1 cm, finger out,
It's about my length, about one centimeter.
100 I'm 1 m, and I'm Mi's little brother.
Don't use me when the object grows, or you will be exhausted.
Usage of greater than sign and less than sign
Greater than symbol, less than symbol, smile at big numbers.
Knowledge points of primary school mathematics
First, carry addition within 20.
Look at a large number, divide it into decimals, round it to ten, and add a fraction.
Master the "ten-point method" and advocate the "recursive method". )
Second, the subtraction of abdication within 20 years
Less than 20 abdicates, and the oral calculation method is simple.
Ten people return one, one person makes up, and the writing is accurate and fast.
Third, the meaning of addition, vertical calculation
When two numbers are added, the result of the addition is called sum.
Don't forget the numbers on the right, one for every ten.
Fourthly, the significance of vertical calculation subtraction.
Subtraction is used from big to small, and the result of subtraction is called difference.
Digital alignment starts from the right, and when it is not enough, take the front position.
Five, two-digit multiplication
Multiplication of two digits is not difficult. There are three points in the calculation process:
The multiplier must be calculated first and then multiplied by ten digits.
The last digit of the product is the key, which is opposite to the ten digits;
After the two products are added up, calculate the number of layers in your mind.
Six, two-digit division
Divide two by two, and two is not enough to divide three.
Except quotient, the remainder is less than divisor.
Then, except for the next item, the test method should be flexible.
Master the "rounding" method and the "same business comparison method".
Understand the semi-definite commercial law and divide the quotient by nine or eight. (where: same head, less high position 1)
Seven, mixed operation
Look at the formula carefully, calculate multiplication and division and add alkali.
When you encounter brackets, you should count them first, and the application rules should be changed.
There are some data to memorize and skills to master.
Eight, fast addition and subtraction
Add and subtract quickly, don't worry, you can see clearly when you get the formula.
Rounded integer close to the whole hundred, the following treatment is not fallacious.
If you don't add enough, you will reduce the complement and add the extra score to the end.
If the subtraction is insufficient, add the complement, and then subtract the excess score.
Nine, multi-digit reading method
The reading method is very simple. First, the fourth grade.
We should start from the highest place, thousands, hundreds, and ten.
Grade units read hundreds of millions, and no zeros are read at the end.
(Don't read the 0 at the end of the stage, and don't read the 0 at the end of the integer)
Read one with a zero in the middle, and the expression of Chinese characters is irrelevant.
Note that the reading is zero:
1, ten thousand levels, the first level has zero.
2, the whole class is zero.
There are zeros at the end of the superior and at the top of the subordinate.
4. There is a 0 in the middle of each level.
X. decimal addition and subtraction
Decimal addition and subtraction calculation problems, with point alignment.
An algorithm is like calculating an integer. After the calculation, move the point down.
XI。 Decimal multiplication
Decimals are multiplied by decimals in the same way as integers.
Fixed product decimal places, factors * * * together.
Twelve, divisor is the division of decimals
Divide the dash of the decimal point, (remove the decimal point)
Move the decimal point of dividend, move it to the right,
The number of decimal places of a divisor determines it.
Thirteen, prime songs
A prime number 2, 3, 5 and 7,
Add 1 before 1, 3, 7 and 9.
After 4, before 3 and 7, after 9 and 7, 1,
Add 7, 1 after 3, 4 and 6,
Add 9, 3 after 2, 5, 7 and 8,
Remember all 25 prime numbers.
Fourteen, fractional multiplication and division method
Fractional multiplication is easy to learn and understand, and numerator and denominator are multiplied separately. The meaning of the formula should be clear, and it is easier to make an appointment. Fractional division is wonderful, changing the original division symbol into multiplication symbol. The divisor is reversed, so calculation is essential.
Fifteen, about the point
Tangent point, tangent point, take the net, save time and effort. From top to bottom, from left to right, make the data clear and don't miss a number. When you encounter a decimal, the decimal point is an integer, and if the number of digits is not enough, use "zero" to make up.
Sixteen, the judgment of prime numbers
Fractional ratio simplification, both ends of prime number. Observe five points: 1 and all the numbers; Two adjacent numbers; The two qualities must be mutual. A large number is a prime number and two numbers are coprime. Decimals are prime numbers, and large numbers are not multiples. (It is a decimal)
Seventeen, the text questions
There are three narrative forms, meaning and name. Remember the method of solving problems clearly, and simplify sentences in one step. Punctuation does not delay the sense of hierarchy. There are two formulaic methods, which can be used as formulas and equations.
XVIII. Application of Comparative Relationship
(A) the phase difference relationship
1 is more or less a big reduction.
2. The proportion of known conditions is more, less than before.
3. The proportion of known conditions is small, and the proportion is reduced first and then increased.
(2) Multiple relationships
1 and time are separated in the problem.
2. Times Under known conditions, multiply before and divide after.
(3) Find a number that is more than (less than) several times.
Divide the multiplier by multiples and add and subtract by how many points.
Add and subtract after division and add and subtract after multiplication.
XIX. Looking for the unit "1"
The unit "1" is cleverly hidden, and I will find you according to the score.
"Among them," standing in front ",yes, accounts for more than" sitting in the back;
"Question and answer" can be found, and supplementary instructions should be done well.
Percentages are often encountered, so it is more polite not to use the word "rate".
Find a pair of good friends, and then determine the multiplication and division number.
Find the description of the cell "1":
Grasp the "key sentences" and "keywords" that contain scores but have no unit names for analysis, thus solving the problem that many students are confused about how to analyze the quantitative relationship. Therefore, letting students learn to quickly find "key sentences" and "keywords" to analyze the quantitative relationship can not only help them master the general law of solving fractional application problems, but also cultivate their ability and develop their intelligence. It is a common learning rule for sixth grade students to "find" first and then "analyze". Remember to guide students to analyze carefully and orderly.
Fractional application problem 1, find 2, understand 3, decide 4, and the corresponding problem-solving ideas.
Twenty, the application of positive and negative ratio
In direct proportion, it is divided into three sections, and the intermediate quantity remains unchanged.
Put them in separate columns and then connect them with an equal sign.
The inverse proportion is divided into three sections, and the constant is in the front.
"If" is divided into total columns and then connected by an equal sign.
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