A formula for calculating the perimeter, area and volume of mathematical geometry in primary schools.
The circumference of a rectangle = (length+width) ×2? C=(a+b)×2 .
The circumference of a square = side length ×4? C=4a .
Area of rectangle = length× width S=ab.
Area of a square = side length × side length s = a.a = a.
Area of triangle = base × height ÷2? S=ah÷2 .
Area of parallelogram = base × height S=ah.
Trapezoidal area = (upper bottom+lower bottom) × height ÷2? s =(a+b)h \2 .
Diameter = radius ×2d=2r Radius = diameter ÷2? r=d÷2 .
Circumference = π× diameter = π× radius× 2? c=πd=2πr .
Area of circle = π× radius× radius.
Area of triangle = base × height ÷2. The formula S=a×h÷2.
Area of a square = side length × side length formula s = a× a.
Area of rectangle = length × width formula s = a × b.
Area of parallelogram = base × height Formula S = a× h.
Trapezoidal area = (upper bottom+lower bottom) × height ÷2 Formula S=(a+b)h÷2.
Sum of internal angles: sum of internal angles of triangle = 180 degrees.
Cuboid volume = length× width× height formula: V=abh.
Volume of cuboid (or cube) = bottom area × height formula: V=abh.
Volume of cube = side length × side length × side length formula: V=aaa.
Circumference = diameter × π formula: L = π d = 2π r.
Area of circle = radius × radius× π formula: s = π R2.
Surface (side) area of cylinder: The surface (side) area of cylinder is equal to the perimeter of bottom multiplied by height. Formula: s = ch = π DH = 2π RH.
Surface area of cylinder: the surface area of 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.
Volume of cylinder: the volume of cylinder is equal to the bottom area multiplied by the height. Formula: V=Sh.
Volume of cone = 1/3 bottom× product height. Formula: V= 1/3Sh.
Law of fractional addition and subtraction: Fractions with the same denominator are added and subtracted, only the numerator is added and subtracted, and the denominator remains the same. Fractions of different denominators are added and subtracted, first divided, then added and subtracted.
The multiplication of fractions is: use the product of molecules as numerator and the product of denominator as denominator.
The law of division of fractions: dividing by a number is equal to multiplying the reciprocal of this number.
Second, unit conversion.
1 km = 1 km 1 km = 1 000m 1 m = 10 decimeter 1 decimeter = 10 cm/kloc-
1 m2 = 100 square decimeter 1 square decimeter = 100 square centimeter 1 square centimeter = 100 square millimeter.
1 m3 = 1000 cubic decimeter 1 cubic decimeter = 1000 cubic centimeter 1 cubic centimeter = 1000 cubic millimeter.
1t =1000kg1kg =1000mg =1kg = 2kg.
1 ha = 10000 m2 1 mu = 666.666 m2.
1 liter = 1 cubic decimeter = 1000 ml 1 ml = 1 cubic centimeter.
1 yuan = 10 angle 1 angle = 10 point 1 yuan = 100 point.
1 century = 100 1 year =1February (3 1 day) has:1\ 3 \ 5 \ 7 \ 8 \1.
February 28th in a normal year, February 29th in a leap year, 365 days in a normal year and 366 days in a leap year, 1 day =24 hours, 1 hour =60 minutes.
1 minute =60 seconds 1 hour =3600 seconds.
Third, the calculation formula of quantitative relationship.
Number of copies × number of copies = total number of copies/number of copies = total number of copies/number of copies = number of copies.
1 multiple× multiple = multiple multiple1multiple = multiple multiple/multiple = 1 multiple.
Speed × time = distance/speed = time/distance/time = speed.
Unit price × quantity = total price/total price = total quantity/quantity = unit price.
Work efficiency × working hours = total workload ÷ work efficiency = working hours ÷ total workload ÷ working hours = work efficiency.
Appendix+Appendix = sum-one addend = another addend.
Minus-Minus = Difference Minus-Difference = Minus+Minus = Minus.
Factor × factor = product ÷ One factor = another factor.
Dividend/Divider = quotient dividend/quotient = divisor quotient × divisor = dividend.
Fourth, arithmetic.
Additive commutative law: Two numbers are added to exchange the position of the addend, and the sum remains the same.
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 is unchanged.
Multiplication and exchange law: when two numbers are multiplied, the position of the exchange factor and the product remain unchanged.
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.
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 is unchanged. Such as: (2+4) × 5 = 2× 5+4× 5.
The essence 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.
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.
Equation: An equation with an unknown number is called an equation.
One-dimensional linear equation: An equation with an unknown number of degree 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.
Fraction: divide the unit "1" into several parts on average, and the number representing such a part or points is called a fraction.
Addition and subtraction of fractions: add and subtract fractions with the same denominator, only add and subtract numerators, and the denominator remains the same. Fractions of different denominators are added and subtracted, first divided, then added and subtracted.
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.
Fraction multiplied by integer, numerator is the product of fractional and integer multiplication, denominator remains unchanged.
Fractions are multiplied by fractions, the product of numerator multiplication is numerator, and the product of denominator multiplication is denominator.
A fraction divided by an integer (except 0) is equal to this fraction multiplied by the reciprocal of this integer.
True fraction: The fraction with numerator less than denominator is called true fraction.
False fraction: Fractions with numerator greater than denominator or numerator equal to denominator are called false fractions. False score is greater than or equal to 1.
With a score: write a false score as an integer, and a true score is called with a score.
The basic nature of the fraction: the numerator and denominator of the fraction are multiplied or divided by the same number (except 0) at the same time, and the size of the fraction remains unchanged.
A number divided by a fraction is equal to the number multiplied by the reciprocal of the fraction.
The number A divided by the number B (except 0) is equal to the reciprocal of the number A multiplied by the number B.