1. multiplication formula nursery rhymes
A frog has a mouth, two eyes and four legs.
Two frogs have two mouths, four eyes and eight legs.
Three frogs have three mouths, six eyes and twelve legs.
Four frogs with four mouths jumped into the water.
2. Numbers divisible by several children's songs
Look at the highest dividend first. A high dividend is not enough.
Quotient is written anywhere except dividend.
If the quotient is less than 1, write 0 to calculate the first and last digits of the quotient.
The remainder should be less than the divisor, so that the operation is correct.
3. Decimal addition and subtraction nursery rhymes
Calculate decimal addition and subtraction, align keys with decimal points,
You can add and subtract by filling the last number with 0.
Decimal size comparison nursery rhymes (self-edited)
Decimal size is relatively easy. Put them all on first.
Decimals and numbers should match, and then compare.
Compare the highest bit first, and the ratio of the highest bit to the low bit is the same.
Finally, it is divided into high and low, which is higher and which is bigger.
Keep it in mind.
Division is the division of decimals
Division is a decimal, so remember to shift.
Move the decimal point to make it an integer,
Move the divisor a few places, and so will the dividend.
If the number of digits is not enough, add 0 to make up the position.
4. Children's songs of elementary arithmetic
Look at the whole project and see if it can be simple;
Take the formula from left to right, multiply first, divide then add and subtract;
Parentheses are small, medium and large, with the number inside first and then outside;
Horizontal calculation and vertical test, step by step is the key.
5. Solve children's songs with application problems
Look at the topic several times to find the key points;
Look at what you want first, and then find conditions;
Reasonable calculation formula, careful calculation;
Ask for more answers to a question, and the unit will not forget it;
Check the results and finally write the answer.
Understanding of length, area, volume and volume
One line is long and has a large area;
Volume takes up space and volume counts.
Step 6 finish children's songs
The rounding method is good, and the approximate figure can be found out by law;
Take which one to look at the next one, and then compare it with five words;
It is 5 big 5 forward 1, and all less than 5 are discarded;
The equal sign is replaced by an equal sign, which makes people understand at a glance.
7. Solving the problem of chickens and rabbits in the same cage
A chicken has two feet, and a rabbit has four.
Count your head and body first. Then press the chicken apart.
8. Operation sequence algorithm
Playing bamboo board, Lian Tian, students listen to me.
I won't talk about other tables and four operations today.
Clear order is the key to the calculation of mixed test questions.
The operation at the same level is the best, counting from left to right.
There are two levels of operations, first multiplication and division, then addition and subtraction.
What should I do if I encounter parentheses? It first appears in parentheses,
After parentheses, the order cannot be out of order.
Every step has been tested, right and happy.
9. abdication reduction method
The abdication subtraction should be kept in mind, starting from the unit;
Who is not enough to retire, don't forget to add ten to the standard;
If the interval is 1, it is best to remember that 0 becomes 10.
10. Successive abdication subtraction
When you see 0, go and see which one has it.
Borrowed and walked back, 0 is a bit like 9.
1 1.
Calculate the application problem in two steps, read and review the problem carefully.
The intermediate problem is the key to solve the problem.
The quantitative relationship should be accurate and the calculation steps should be clear.
Grasp both ends of the middle band and answer the questions accurately.
12. Reading French songs with multiple digits
Reading should start from a high position, and whoever reads it several times;
If there is a zero at the end of each level, there is no need to remember it in your mind;
Other numbers are zero in a row, read only one digit, and remember them carefully;
Reading at the end of ten thousand levels? Wan? , add reading at the end of the billion level? Billion? ,
Always remember the reading rules.
13. Writing songs with multiple digits
Write numbers from the top and write as many as you want.
Who doesn't have a unit to use? 0? Remember the top position.
14. 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 as the size, and the high position is known.
15. Multi-digit rewriting song
Behind ten thousand people? 0? Remove it, add 10 thousand words and change it.
Behind a billion bits? 0? Remove it and add a billion words to change it.
A phrase about the actual comparison of plans.
I plan to actually compare the application problems and analyze them carefully, so don't worry.
The quantitative relationship is very important, and the relationship before and after is very subtle.
Write the relationship first, which leads to the solution to the problem.
The plan is actually in front, compare a line up and down.
The specific quantity should be reflected, and the constant quantity is the key.
Look at it accurately according to the number of days, and then fill in the blanks.
According to the equation, the arithmetic method is also simple.
16. What about the party? Ten? French
Think of 1 when you see 9, and think of 2 when you see 8.
Think of 3 when you see 7, and think of 4 when you see 6.
When you see the big corner decimal system, switch the two numbers first.
10 shares
9 and 1, naughty
7, 3, 8 and 2 are also naughty.
Blow 6 liters 4 (6 like a whistle, 4 like a flag)
What a clever little hand (let the students shake hands like dividing 10 into 5 and 5)
17. Multiplication formula of commercial songs:
(1) If you want to multiply and divide, you can tell me what is missing in the formula.
(2) To find the quotient by multiplication formula, first think carefully about the formula:
If a number is missing, it is a quotient.
18. Children's songs about knowing time
When the hand passes the number, it will show the time.
If you want to ask how many points you got, please look at the minute hand carefully.
For some simple subtraction operations:
If you increase more, you will decrease, and if you increase less, you will increase more;
If you reduce more, you will increase, and if you reduce it, you will reduce it again.
The law of association is not difficult. Let's calculate the combination of two numbers first.
19. The problem of planting trees
Children, open your hands. Everyone has five fingers.
There are some gaps between your fingers. Please take a closer look.
Division in which the middle or last bit of quotient is 0.
I am 0, and I am good at division.
Not enough quotient 1. I'll make it up to you. I will sit when there is a vacancy.
If others want to get rid of me, I will always be the winner.
20. The meaning of division
Arrive? Except? , a circle, Except? The word is preceded by a divisor,
? Except? Don't forget to change the position of the dividing line after the word.
Four operation sequences
Parentheses grab the first place, and multiplication and division rank second.
Finally, add and subtract. Whoever comes first counts first.
Successive abdication subtraction
When you see 0, go and see which one has it.
Borrowed and walked back, 0 is a bit like 9.
2 1.
I said one, one, one, one, a piece of paper, a pen,
You need a pen and paper to study math and do exercises.
I said two, two, two, two. How many twos do I have?
Count left, right, left, eyes, hands, feet and ears.
I said three, three, three, three, put a fresh red scarf on your chest,
We like three corners and three sides.
I said four, four, four, four. There is a long table in front of me.
Four corners, four faces, use it to read and write.
I said five, five, five, five, five, five-pointed star, shining,
There are five stars on the national flag, and I am the little star.
I said 6666. I'm so happy.
Singing, dancing and playing games, the flowers of the motherland are really happy.
I said seven, seven, seven, seven days a week,
Don't go to school on Sunday, be a good helper for your mother.
I said eight, eight, eight, eight, condolences to the families,
You sweep the floor, I clean the windows, and my aunt laughs at me.
I said September 10 teacher's day,
Respect teachers and be polite to others. Everyone praised my good baby.
When I say ten, ten, and both hands have fingers,
Ten fingers are very useful. Do good deeds like Lei Feng.
Hour hand and minute hand
The small dial goes round and round, and the hour hand goes round and round.
The minute hand is long, the hour hand is short, one is fast and the other is slow.
The minute hand ran a full circle, and the hour hand only ran a short one.
22. abacus reading and writing
The abacus is magical, and reading and writing numbers is the easiest.
The four-digit level is the key, and reading and writing all start from the high position.
Read one of the zeros before the stage, and don't read them after the stage.
100 million and 10 thousand imitations, and then add units after reading them.
Write it down level by level, and the beads are not occupied by beam 0.
23. Comparison of multi-digit sizes
The number of digits depends on the number of digits, and the number of digits is large;
If you look at the high digits with the same number of digits, the high digits are large.
24. Year, month and day
One, three, five, seven, eight, ten, wax, 3 1 day is always big.
April, June, September, November, 30 days is never bad.
February, the most special, February and February changes.
Twenty-nine leap years and twenty-eight average years.
Except the year number is even, the whole century number is marked with double zeros.
There are two ways to be punctual, twenty-four and ordinary.
The time unit is lined up, and the largest unit is the century.
1 century, 100 year; How many days is 1 year? 365 in a normal year and 366 in a leap year.
1 hour 60 minutes 1 minute equals 60 seconds.
Remember the year, month, day, hour, minute and second, and the progressive rate.
25. Score comparison
When comparing scores, remember both numerator and denominator.
The denominator is the same. If you look at molecules, the bigger the molecules, the greater the score.
If the numerator is the same, look at the denominator, and the score with a large denominator is small.
26. Integer addition and subtraction rules
1. Integer addition rule
Integer addition is regular, and the same digits should be aligned.
And less than ten fell in the original position, and more than ten entered one.
Go down for more than ten times, and add whichever one is dropped.
Add up the carry, and the result is not less than half a cent.
2. Integer subtraction rules
Integer subtraction is regular, and the same numbers should be aligned.
Reduce the time and difference greatly, and borrow less.
Minus ten and add it, and the result of addition and subtraction falls in the original position.
Be careful when borrowing continuously, and remember what is left when borrowing.
27. Integer multiplication rules
1. One-digit multiplication rule
Integer multiplication starts with the lowest bit, and one-digit multiplication is a product.
Multiply the number of units by several 1, and the last digit of the product is the number of units.
The calculation is accurate and the multiplication formula has a basis.
2. Two-digit multiplication rule
Integer multiplication starts with the lowest bit, and two-digit multiplication is twice the product.
Multiply the number of units by several 1, and the last digit of the product is the number of units.
Ten digits are multiplied by dozens, and the last digit of the product is ten digits.
Calculate the correct number of digits and add the two products.
3. Multi-digit multiplication rules
Integer multiplication starts from the low bit and several numbers are multiplied several times.
Multiply the number of units by several 1, and the last digit of the product is the number of units.
Ten digits are multiplied by dozens, and the last digit of the product is ten digits.
Hundreds times hundreds, and the last digit of the product is hundreds.
Calculate the correct position and add several products together.
4. Multiplication rule with zero at the end of the factor
If there is a 0 at the end of the factor, write it after it without multiplying it first.
Multiply the product to make up 0 and write a few zeros.
28. Law of integer division
1. Divider is the division rule of one digit.
Integer division starts from the high order. One by one.
One is not enough to see two, except which business is which.
The remainder is less than the divisor, which is not enough for quotient one zero.
2. Divider is the division rule of two digits.
Integer division starts from the high order. Divide by two. Look at two.
Two is not enough to see three, except which business is which.
The remainder is less than the divisor, which is not enough for quotient one zero.
3. Multi-digit division rule
Integer division starts from the high order. Divide by a few and see how many there are.
This is not enough to see the next one, except which business is which.
The remainder is less than the divisor, which is not enough for quotient one zero.
4. The nature of quotient invariance
Dividend and divisor are multiplied at the same time, and the multiplication factors should be the same.
Divider and divisor are divided by the same number.
Multiply everything except 0,
Remember the immutability of quotient.
29. Quaternary arithmetic
1. Decimal addition and subtraction rules
Decimals are added and subtracted regularly, and the same numbers should be aligned.
One for one, ten for ten.
Ten to ten, percentile to percentile.
In short, the decimal points should be aligned.
The calculation result is decimal, and the zero at the end should be crossed out.
2. Decimal multiplication rules
Starting from the low order of decimal multiplication, calculate the product by integer first.
Look at the decimal places in the factor.
Just count a few points from the right side of the product, and finally there are zeros to cross out.
3. Law of fractional division
Decimal division starts from the high position, and look for the law of divisor.
Divider is a direct division of an integer, except which manufacturer.
Not enough quotient 10, the quotient and dividend points are aligned.
The divisor is a decimal to an integer, and the divisor decimal point is shifted in the same place.
If the number on the right is not enough, it should be filled with zeros.
30. Comparison of decimal size
The decimal size depends on the high position, and the number of hours is large when the integer is large.
If the integers are the same, there will be more decimal places and more hours.
When the deciles are the same, the greater the percentile, the longer the working time.
Thirteen. Basic Properties of Numbers and Four Arithmetic Rules
Basic properties of 1. fraction
The numerator and denominator are multiplied at the same time by the same factor.
The numerator and denominator are divided by the same number.
Multiply everything except 0,
The size of the fractional value will not change.
2. Fraction addition and subtraction rules
Adding and subtracting fractions is very simple, and unifying units is the key.
Use the denominator to add and subtract fractions, only add and subtract numerators, and the denominator size remains the same.
Fractions with different denominators are added and subtracted, and the fractions are divided first and then calculated.
3. Fractional multiplication rules
Fractional multiplication is simpler and numerator and denominator are calculated separately.
Multiplication of numerator is numerator and multiplication of denominator is denominator.
The numerator and denominator are not prime numbers, so the numerator and denominator should be calculated first.
4. Law of fractional division
Fractional division is the simplest, and it is calculated by conversion multiplication.
When the divisor becomes a multiplier, the reciprocal of the divisor will appear.
3 1. Mixed operation sequence songs
The mixed operations are in sequence, starting from the left side of the peer calculation.
Add, subtract, multiply and divide mixed problems, calculate multiplication first, and then remember division.
If there are brackets, count the questions in brackets first.
Two-step and three-step application problem analysis ballads
A small question mark locking problem, grasp the key to analyze.
Convert known conditions into numbers and find out all relevant conditions.
Look at the serial number of the clause, and the correct formulation is no problem.
32. Letters represent numbers
Letters represent numbers, so remember that when omitting the multiplication sign, the numbers should be written in front and the letters should be written behind.
The same factor changes the cardinal number, and the number of factors changes the exponent.
The multiplication sign can be abbreviated as a dot, and the addition and subtraction multiplication sign cannot be lost.
33. Solve application problems with column equations
Column equation to solve application problems, grasp the key points to analyze.
Turn known conditions into numbers and unknown conditions into letters,
Find the relevant algebraic expressions and connect them to read.
34. The unit of measurement is.
Children, line up quickly and go to work hand in hand. Let's see who speaks fast. That's right.
The unit of RMB is Yuan, Jiao and Min, and the forward speed is 10, remember.
1 yuan got 10 angle; The angle of 1 is 10, and 1 yuan is equal to 100.
What is the unit of length and the progressive rate?
Megameter, centimeter and millimeter.
The maximum unit is kilometers.
1 m = 10 decimeter, 1 decimeter = 1 0cm,1cm =10mm.
The meter and the kilometer are also adjacent, and the rate 1000 is a special case.
What is the unit of mass and what is the progressive rate?
Tons, kilograms and grams,
Remember the ratio of 1000.
Physical units are easier. Adjacent 100 is the area and adjacent 1000 is the volume.
Large units, small units and size conversion are all regular.
From large to small, the decimal point moves to the right; Divided by the forward speed, the decimal point moves to the left.
Propulsion rate 10, shifted by one place; The propulsion rate is 100, shifting by two places; The propulsion rate is 1000, which is displaced by three places.
35. The meaning of divisibility of numbers
Remember that all items in the divisibility of numbers should be integers.
But the divisor is not equal to 0, and the quotient is an integer with no remainder.
Answer? When using b, it can be said that the number b is divisible by a, and the number a is divisible by B.
A is a multiple of b, and b is a divisor of a.
If you want to find the divisor, you can remove the natural number.
If you want to multiply, multiply by natural numbers.
Numbers divisible by 2, 5 and 3.
Units are 0 and 5 and must be divisible by 5.
The units are 2, 4, 6, 8 and 0, and they must be divisible by 2.
If the sum of each number is a multiple of 3, it must be divisible by 3.
36. Prime numbers and composite numbers
The key to distinguish prime numbers from composite numbers is to look at divisors.
1 has only one divisor, which is neither prime nor composite;
If there are only two divisors, it must be a prime number;
Three divisors or more, it must be a composite number.
37. prime factor decomposition
The decomposition of prime factors is realized by short division.
Divisor is a prime number, and quotient is also a prime number.
The expression is simple: composite number = prime number? prime number
Common divisor, common multiple and prime number
Common divisor, common multiple, what is the key? Public? Remember.
The common divisor is called the common divisor and the greatest common divisor is called the greatest common divisor.
If the common divisor is only 1, it is called a prime number.
Common multiples are called common multiples. The least common multiple is called the least common multiple.
There are differences in seeking laws, so don't make mistakes
Short division is only multiplied by divisor to find the greatest common divisor.
The divisor and quotient must be multiplied, which is to find the least common multiple.
38. Circle, cylinder and cone
Both production and life need good circle knowledge.
To draw a circle, find a fixed point, and the center of the circle determines the position of the circle.
The radius determines the size of the circle.
In the same circle or equal circle, diameter =2 radius.
The circumference and area of a circle are inseparable from pi.
If the condition is radius, the circumference of the circle is 2? r，？ R2 is a region.
If the condition is diameter, what is the circumference of the circle? d .
The perimeter of the circle multiplied by the height of the cylinder is the side area of the cylinder.
The area of the circle multiplied by the height of the cylinder is the volume of the cylinder.
To find a cone with the same base and height, you only need to multiply it by one third.
39. The application of percentages and scores.
Percentage, percentage, also known as percentage.
This only means that one number is a few percent of another.
The denominator is 100, remember.
Percentages and decimals are regular.
Add a hundred semicolons after the decimal point and move the decimal point to the right.
Remove the percent sign and move the decimal point to the left.
The same principle applies to percentages and fractions.
Read it and think about who can compete with whom.
The application problem of percentage score,
Key decision unit one.
Look at the components to find the scoring rate,
One-to-one correspondence is a rule
If the number of units is known,
Just ask for a fraction or several times of it.
If the number of units is unknown,
Analyze the equation.
The known conditions are converted into numbers,
Unknown conditions, changing letters,
Find out the relevant algebraic expressions,
Connect and read.
Difference and connection of ratio, division and fraction
Remember proportion, division and fraction, connection and difference.
The front part of the ratio is equivalent to the numerator and dividend of the fraction;
The latter term of the ratio is equivalent to the denominator and divisor of the fraction;
Comparison symbols are equivalent to division symbols and fractional lines;
It is crucial to distinguish clearly.
Ratio is the relationship between two quantities, division is an operation,
The score is just a number,
Their properties are closely linked.
The divisor and the divisor are multiplied at the same time, and the multiplication factors should be the same? ..)
The former and the latter are multiplied at the same time, and the multiplication factors should be the same.
The former and the latter are divided by the same amount.
Multiply all numbers except zero,
The size of the ratio remains the same.
40.scale
1. It is easy to find the scale.
First, unify the units and write the ratio of the drawing distance to the actual distance.
Then according to the basic properties, the score is reduced, and the former ratio is 1.
2. The scale application problem, the actual distance is unit one.
If a unit quantity is known, find its fraction or multiple.
If the unit quantity is unknown, make an equation to analyze it.
The Significance, Nature and Positive and Negative Proportion of Proportion
Proportion of components.
The basic nature of proportion should be kept in mind:
The product of that inn term is equal to the product of the outer term,
According to the solution ratio.
One quantity varies with another,
When the quotient is constant, it is proportional, and when the product is constant, it is inversely proportional.
According to the meaning sequence equation, it is the easiest to integrate.
Addition and subtraction of rational numbers:
The addition and subtraction of rational numbers is very simple, and the sign rule is the key.
The same sign is the same as the plus sign, and the difference sign is reduced.
A number with a larger absolute value, with the symbol written before the result.
4 1. rational number multiplication
Multiplication of rational numbers, remember,
Multiply two numbers with positive and negative signs.
Any number multiplied by 0 is 0,
The number of negative factors determines the positive and negative product.
The product of even negative factors is positive,
The product of odd negative factors is negative.
Rational number division rule
Rational number division is the simplest, and it is calculated by conversion multiplication.