1. Area of triangle = base × height ÷2 Formula: S= a×h÷2.

2. Square area = side length × side length formula: S = a× a.

3. area of rectangle = length× width formula: S= a×b

4. area of parallelogram = base× height formula: S= a×h

5. Trapezoidal area = (upper bottom+lower bottom) × height ÷2 Formula: S=(a+b)h÷2.

6. Sum of internal angles: sum of internal angles of triangle = 180 degrees.

7. cuboid volume = length× width× height formula: V=abh

8. cuboid (or cube) volume = bottom area × height formula: V=abh.

9. Volume of cube = side length × side length × side length formula: V=aaa.

10. circumference of a circle = diameter × π formula: l = π d = 2π r.

1 1. Area of circle = radius× radius× π formula: s = π R2.

12. Surface (side) area of the cylinder: the surface (side) area of the cylinder is equal to the perimeter of the bottom multiplied by the height.

Formula: s = ch = π DH = 2π RH.

13. Surface area of the cylinder: the surface area of the cylinder is equal to the perimeter of the bottom multiplied by the height plus the area of the circles at both ends.

Formula: S=ch+2s=ch+2πr2.

14. Volume of cylinder: the volume of cylinder is equal to the bottom area multiplied by the height formula: V=Sh.

15. cone volume = 1/3 bottom× product height formula: V= 1/3Sh.

The Formula of Elementary School Mathematics Definition Theorem (2)

First of all, arithmetic.

1. additive commutative law: Two numbers are added to exchange the position of addend, and the sum is unchanged.

2. The law of addition and association: When three numbers are added, the first two numbers are added first, or the last two numbers are added first, and then the third number is added, and the sum remains unchanged.

3. Multiplication and exchange law: when two numbers are multiplied, the position of the exchange factor remains unchanged.

4. Multiplication and association law: When three numbers are multiplied, the first two numbers are multiplied, or the second two numbers are multiplied first, and then the third number is multiplied, and the product remains unchanged.

5. Multiplication and distribution law: When two numbers are multiplied by the same number, you can multiply the two addends by this number respectively, and then add the two products, and the result remains unchanged. Such as: (2+4) × 5 = 2× 5+4× 5.

6. Nature of division: In division, the dividend and divisor are expanded (or reduced) by the same multiple at the same time, and the quotient remains unchanged. Divide 0 by any number other than 0 to get 0.

7. Equation: An equation in which the value on the left of the equal sign equals the value on the right of the equal sign is called an equation. Basic properties of the equation: When both sides of the equation are multiplied (or divided) by the same number at the same time, the equation is still valid.

8. Equations: Equations with unknowns are called equations.

9. One-dimensional linear equation: An equation with an unknown number of 1 is called a one-dimensional linear equation.

Example method and calculation of learning linear equation of one variable. That is, an example is given to illustrate that the formula is replaced by χ and calculated.

10. Score: divide the unit "1" into several parts on average, and the number representing such a part or points is called a score.

1 1. Addition and subtraction of fractions: add and subtract fractions with denominator, only add and subtract numerators, and the denominator remains unchanged. Fractions of different denominators are added and subtracted, first divided, then added and subtracted.

12. Comparison of fraction size: Compared with the fraction of denominator, the numerator is large and the numerator is small. Compare the scores of different denominators, divide them first and then compare them; If the numerator is the same, the denominator is big and small.

13. Fractions are multiplied by integers, and the product of the multiplication of fractions and integers is a numerator, and the denominator remains unchanged.

14. Fractions are multiplied by fractions, the product of numerator multiplication is numerator, and the product of denominator multiplication is denominator.

15. Fraction divided by integer (except 0) equals fraction multiplied by the reciprocal of the integer.

16. True fraction: The fraction with numerator less than denominator is called true fraction.

17. False fraction: the fraction with numerator greater than denominator or numerator equal to denominator is called false fraction. False score is greater than or equal to 1.

18. With score: write the false score as an integer, and the true score is called with score.

19. The basic nature of the fraction: the numerator and denominator of the fraction are multiplied or divided by the same number at the same time (except 0), and the size of the fraction remains unchanged.

20. A number divided by a fraction is equal to the number multiplied by the reciprocal of the fraction.

2 1.A divided by b (except 0) equals the reciprocal of a multiplied by b.

Second, the calculation formula of quantitative relationship

1. unit price × quantity = total price

2. Single output × quantity = total output

3. Speed × time = distance

4. Work efficiency × time = total workload

5. Addition, subtraction, multiplication and division

(1) Appendix+Appendix = sum

(2) One addend = and+ another addend

(3) minuend-minuend = difference

(4) Negative = negative difference

(5) Minus = Minus+Difference

(6) Factor × factor = product

(7) One factor = product ÷ another factor

(8) Dividend = quotient

Divider = dividend quotient

(10) Divider = quotient × divisor

(1 1) Division with remainder:

(12) Divider = quotient × divisor+remainder

6. Unit conversion

(1) 1 km = 1 km = 1 km = 1000 m 1 m = 10 decimeter

1 decimeter = 1 0cm1cm =10mm

(2) 1 m2 = 100 square decimeter 1 square decimeter = 100 square centimeter.

1 cm2 = 100 mm2

(3) 1 m3 = 1000 cubic decimeter

1 cm3 = 1000 cm3

(4) 1t = 1000kg 1kg = 1000mg = 1kg = 1kg。

(5) 1 hectare = 1 ten thousand square meters 1 mu = 666.666 square meters.

(6) 1 liter = 1 cubic decimeter = 1000 ml 1 ml = 1 cubic centimeter.

I. conversion of length unit 1 km =1000m1m =1decimeter1decimeter =10cm =10. Area unit conversion 1 km2. M 1 m2 = 100 square decimeter 1 square decimeter = 100 square centimeter 1 square centimeter = 100 square millimeter three. Unit of volume conversion 1 m3 = 1000 cubic decimeter. 0 m3 = 1000L 1 decimeter cubic = 1 centimeter cubic = 1 milliliter IV. Unit of weight conversion 1 ton = 1 000kg/kg = 100g. 0 yuan = 1 0 angle/kloc-0 angle = 10 minute 1 0. Hour =3600 seconds, big month (3 1 day): 1, 3, 5, 7, 8, 10, 12, small month (30 days): 4, 6, 9,/kloc-.

7. Ratio: The division of two numbers is called the ratio of two numbers. Such as: 2÷5 or 3∶6 or 1/3. The first and second items of the ratio are multiplied or divided by the same number at the same time (except 0), and the ratio remains unchanged.

8. Proportion

(1) Definition: Two expressions with equal ratios are called proportions. Such as: 3 ∶ 6 = 9 ∶ 18.

(2) Basic properties: In proportion, the product of two external terms is equal to the product of two internal terms.

(3) Solution ratio: The unknown term in the ratio is called solution ratio. Such as 3: χ = 9:18.

(4) Proportion: two related quantities, one changes and the other changes. If the corresponding ratio (i.e. quotient k) of these two quantities is certain, these two quantities are called proportional quantities, and their relationship is called proportional relationship.

For example: y/x=k( k must) or kx = y.

(5) Inverse proportion: two related quantities, one changes and the other changes. If the product of the corresponding two numbers in these two quantities is certain, these two quantities are called inverse proportional quantities, and their relationship is called inverse proportional relationship.

For example: x×y = k( k must) or k/x = y.

(6) Percentage: The number indicating that one number is the percentage of another number is called percentage. Percentage is also called percentage or percentage.

9. Decimals, Fractions and Percentages

(1) To convert decimals into percentages, just move the decimal point two places to the right, followed by hundreds of semicolons. In fact, to turn a decimal into a percentage, just multiply this decimal by.

100% will do.

(2) To convert percentages into decimals, just remove the percent sign and move the decimal point two places to the left.

(3) Convert fractions into percentages, usually by converting fractions into decimals (except infinity, three decimal places are usually reserved), and then converting decimals into percentages. In fact, to turn a fraction into a percentage, you must first turn the fraction into a decimal and then multiply it by 100%.

(4) the percentage of the number of components, first rewrite the percentage of the number of components, can be turned into the simplest fraction.

10. greatest common divisor: several numbers can be divisible by the same number at the same time, and this number is called the greatest common divisor of these numbers. (or the common divisor of several numbers is called the common divisor of these numbers. The largest one is called the greatest common divisor. )

1 1. prime number: the common divisor has only two numbers, which is called prime number.

12. Least common multiple: the common multiple of several numbers is called the common multiple of these numbers, and the smallest is called the least common multiple of these numbers.

13. Comprehensive score: changing scores of different denominators into scores of the same denominator is equal to the original score, which is called comprehensive score. (Common divisor is the least common multiple)

14. approximation: it is called approximation to change a fraction into a fraction equal to it, but with smaller numerator and denominator. (The greatest common divisor is used for divisor)

15. simplest fraction: A fraction whose numerator and denominator are prime numbers is called simplest fraction.

At the end of (1) fraction calculation, the number must be converted into the simplest fraction.

(2) Numbers with digits of 0, 2, 4, 6 and 8 can all be divisible by 2, that is, they can be subtracted by 2.

(3) A number with 0 or 5 digits can be divisible by 5, that is, it can be reduced by 5.

16. Even and odd numbers: Numbers divisible by 2 are called even numbers. Numbers that are not divisible by 2 are called odd numbers.

17. Prime number (prime number): If a number only has 1 and two divisors of itself, it is called a prime number (or prime number).

18. Complex number: A number is called a complex number if it has other divisors besides 1 and itself. 1 is neither prime nor composite.

19. Interest = principal × interest rate× time (time is usually in years or months, which should correspond to the unit of interest rate).

20. Interest rate: The ratio of interest to principal is called interest rate. The ratio of interest to principal for one year is called annual interest rate. The ratio of interest to principal in January is called monthly interest rate.

2 1. natural number: an integer used to represent the number of objects, called a natural number. 0 is also a natural number.

22. Cyclic decimal: a decimal, starting from a certain place in the decimal part, and one or several numbers are repeated in turn. Such decimals are called cyclic decimals. Such as: 3. 14 14 14.

23. Acyclic decimal: a decimal, starting from the decimal part, without one number or several numbers appearing in turn repeatedly. Such a decimal is called acyclic decimal. Such as: 3. 14 1592654.

24. Infinitely circulating decimal: a decimal, from the decimal part to the infinite digits, is called infinitely circulating decimal without one number or several numbers appearing repeatedly. Such as 3. 14 1592654. ...

25. Algebra: Use letters instead of numbers.

26. Algebraic formulas: Formulas expressed by letters are called algebraic formulas. For example 3x = AB+C.

This is all the formulas in primary schools.