1. The circumference of a rectangle = (length+width) ×2C=(a+b)×2.
2. The circumference of a square = side length ×4C=4a
3. Area of rectangle = length× width S=ab
4. Area of a square = side length × side length S = a.a = a.
5. Area of triangle = base × height ÷2S=ah÷2.
6. Area of parallelogram = base × height S=ah
7. trapezoidal area = (upper bottom+lower bottom) × height ÷2S=(a+b)h÷2.
8. Diameter = Radius× 2D = 2r Radius = Diameter ÷2r=d÷2
9. The circumference of a circle = π× diameter = π× radius× 2c = π d = 2π r.
10. Area of circle = π× radius× radius
1 1. Area of triangle = base × height ÷2. The formula S=a×h÷2.
12. square area = side length × side length formula s = a× a.
13. area of rectangle = length× width formula S=a×b
14. area of parallelogram = base× height formula S=a×h
15. trapezoidal area = (upper bottom+lower bottom) × height ÷2 formula S=(a+b)h÷2.
16. sum of internal angles: sum of internal angles of triangle = 180 degrees.
17. cuboid volume = length× width× height formula: V=abh
18. cuboid (or cube) volume = bottom area × height formula: V=abh.
19. Volume of cube = side length × side length × side length formula: V=aaa.
20. The circumference of a circle = diameter× π formula: L=πd=2πr
2 1. Area of circle = radius× radius× π formula: S=πr2.
22. Surface (side) area of cylinder: The surface (side) area of cylinder is equal to the perimeter of the bottom multiplied by the height. Formula: S=ch=πdh=2πrh.
23. Surface area of a cylinder: The surface area of a 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.
24. Volume of cylinder: The volume of cylinder is equal to the bottom area multiplied by the height. Formula: V=Sh
25. The volume of the cone = 1/3 bottom× product height. Formula: V= 1/3Sh
26. Addition and subtraction of scores: add and subtract scores 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.
27. Multiplication of fractions: use the product of molecules as numerator and the product of denominator as denominator.
28. The law of division of fractions: dividing by a number is equal to multiplying the reciprocal of this number.
Two. Unit conversion
1.1km =1km =1000m1m =10 decimeter1decimeter =10cm/kloc-.
2. 1 m2 = 100 square decimeter 1 square decimeter = 100 square centimeter 1 square centimeter = 100 square millimeter.
3. 1 m3 = 1000 cubic decimeter 1 cubic decimeter = 1000 cubic centimeter 1 cubic centimeter = 1000 cubic millimeter.
4.1t =1000 kg1kg =1000 mg =1kg = 2 kg.
5. 1 ha = 10000 m2 1 mu =666.666 m2.
6. 1 liter = 1 cubic decimeter = 1000 ml 1 ml = 1 cubic centimeter.
7. 1 yuan = 10 angle 1 angle = 10 point 1 yuan = 100 point.
8. 1 century = 100 1 year =1February (3 1 day) has:1\ \ 3 \ \ 5 \ \ 7.
9. 28 days in a normal year and 29 days in a leap year; 365 days in the balance year and 366 days in the leap year; 1 day =24 hours; 1 hour =60 minutes.
10. 1 minute =60 seconds 1 hour =3600 seconds.
Third, the calculation formula of quantitative relationship
1. per share × number of shares = total number of shares = total number of shares = number of shares = number of shares.
2. 1 multiple× multiple = multiple +0 multiple = multiple +0 multiple = multiple = 1 multiple.
3. Speed × time = distance/speed = time/distance/time = speed
4. Unit price × quantity = total price ÷ unit price = total quantity ÷ quantity = unit price
5. Work efficiency × working hours = total workload ÷ work efficiency = working hours ÷ total workload ÷ working hours = work efficiency.
6. Appendix+Appendix = sum-one addend = another addend
7. Minus-Minus = Minus-Minus = Minus+Minus = Minus
8. Factor × factor = product ÷ one factor = another factor.
9. Dividend = quotient dividend = divisor quotient × divisor = dividend
Fourth, 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. Fraction multiplied by fraction, product multiplied by numerator is numerator, product multiplied by denominator is denominator.