Unit 1 decimal multiplication 1, decimal multiplication integer? The meaning of P2 and 3 —— A simple operation to find the sum of several identical addends. Like what? 1.5×3 is a simple calculation of several times or the sum of three 1.5. Calculation method? Expand the decimal into an integer first? Calculate the product according to the law of integer multiplication? How many decimal places does a factor have? Just count a few points to the right of the product and decimal point. 2. Decimal times decimal? P4 means, 5 is to find a fraction of this number. Like what? 1.5×0.8 is eight tenths of 1.5. How much is 1.5× 1.8? It is 1.8 times 1.5. Calculation method? Expand the decimal into an integer first? Calculate the product according to the law of integer multiplication? How many decimal places does a factor have? Just count a few points to the right of the product and decimal point. Attention? In the calculation results? Do you want to delete the 0 at the end of the decimal part? Simplified decimals? When there are not enough decimal places. Use 0 as a placeholder. 3. regularity? 1P9 is a number? Except 0? Multiply by a number greater than 1 Is the product larger than the original quantity? A number? Except 0? Multiply by a number less than 1 The product is less than the original quantity. 4. There are generally three methods to find the divisor: P 10? (1) rounding method? (2) into law? (3) Truncation method 5. Calculate the money? Keep two decimal places? Represents the calculation of this point. Leave a decimal place to indicate that the angle has been calculated. 6、? P 1 1？ The order of decimal four operations is the same as that of integers. 7. What are the operational rules and properties? Addition? Additive commutative law? A+b=b+a Addition Law: (a+b)+c=a+(b+c) Subtraction? Subtraction attribute? A-b-c=a-(b+c) a-(b-c)=a-b+c Multiplication? Multiplication commutative law? A×b=b×a multiplicative associative law? (a×b)×c=a×(b×c) Multiplication and Distribution Law? (a+b)×c=a×c+b×c(a-b)×c=a×c-b×c division? The nature of division? A÷b÷c=a÷(b×c) unit 2 fractional division 8. What is the meaning of fractional division? Know the product of two factors and one of them? The operation of finding another factor. Like what? 0.6÷0.3 means that the product of two known factors is 0.6, and one of them is 0.3? The operation of finding another factor.

9. How to divide a decimal by an integer? P 16 decimal divided by integer? Divide by an integer. ? The decimal point of quotient should be aligned with the decimal point of dividend. Is the integer part not divided enough? Quotient 0? Point the decimal point. What if there is a remainder? Add 0 and then divide. 10、? P2 1？ How to calculate the division in which the divisor is a decimal? Expand the divisor and dividend by the same multiple first? Turn a divisor into an integer? Then it is calculated according to the rule of fractional division in which the divisor is an integer. Attention? What if the dividend number is not enough? Supplement the dividend with 0 at the end. 1 1, (P23) in practical application? The quotient obtained by fractional division can also be rounded to a certain number of decimal places as needed? Find the divisor of quotient. 12, (p24,25) division? (1) Quotient Invariant Property? Dividend and divisor expand or shrink by the same factor at the same time? 0 remains unchanged except for foreign businessmen. ② The divisor remains the same? Dividend expansion? With the expansion of business. (3) Is the dividend the same? Frequency divider reduction? Business development. 13, (P28) cyclic decimal? The fractional part of a number? Start with someone? One number or several numbers appear repeatedly in turn. This decimal is called a recurring decimal. Round festival? Decimal part of cyclic decimal? Numbers that repeat in turn. For example, the period of 6.3232 is 32. 14, and the number of decimal places is limited. It's called a finite decimal. Is the number of decimal places infinite? It's called infinite decimal. Unit 3 Observing Objects 15, Observing Objects from Different Angles? The shape you see may be different. When observing a cuboid or cube? You can see up to three faces from a fixed position. Unit 4 Simple Equation 16? P45？ In a formula containing letters? The multiplication sign in the middle of the letter can be written as ""? It can also be omitted. The plus sign, minus sign, division sign and multiplication sign between numbers cannot be omitted. 17, a×a can be written as a or a? A is pronounced as the square of a, and 2a stands for a+a 18. Equation? Equations with unknowns are called equations. The value of the unknown that makes the left and right sides of the equation equal? This is called the solution of the equation. The process of solving an equation is called solving an equation. 19, the principle of solving equations? Balance. The left and right sides of the equation add, subtract, multiply and divide the same number at the same time? Except for 0, the equation still holds. 20, 10 quantity relationship? Addition? Sum = Addendum+Addendum One Addendum = and-Two Addendums Subtract? Difference = minus-minus-minus = minus+minus = minus-minus multiplication? Product = factor × factor-factor = product ÷ another factor divided by? Quotient = Divider-Divider Divider = Quotient × Divider = Divider-Divider-Divider-Divider-Quotient

2 1, all equations are equations? But all equations are not necessarily equations. 22, the equation of the test process? The left side of the equation = 23, and the solution of the equation is a number? Calculation process of solving equations. = Right side of the equation. So what? X=？ Is the solution of the equation. The area of the fifth unit polygon 23, formula? Rectangular? Circumference = (length+width) ×2- length = circumference ÷2- width? Width = circumference ÷2- Long letter formula? C=(a+b)×2 area = length× width letter formula? S=ab squared? Perimeter = side length ×4 letters formula? C=4a area = side length × side length letter formula? S = area of parallelogram = base × high letter formula? S=ah triangle area = bottom × height ÷2- bottom = area × 2 height? Height = area × 2 ○ letter formula? S=ah÷2 trapezoidal area =? Upper sole+lower sole? × Gao ÷2 letter formula? S=？ a+b？ H÷2 Upper bottom = area ×2÷ height? Bottom? Bottom = area ×2÷ height-upper bottom? Height = area ×2 \u? Upper sole+lower sole? 24. Derivation of parallelogram area formula? How to deduce the formulas of shear, translation and triangle area? Can a rotating parallelogram be transformed into a rectangle? Two identical triangles can form a parallelogram? Is the length of a rectangle equal to the base of a parallelogram? The base of parallelogram is equivalent to the base of triangle? Is the width of a rectangle equal to the height of a parallelogram? Is the height of parallelogram equal to the height of triangle? Is the area of rectangle equal to the area of parallelogram? The area of parallelogram is equal to twice the area of triangle? Because rectangular area = length x width? So parallelogram area = base x height. Because parallelogram area = base × height? So the triangle area = base × height ÷ 26, and the trapezoid area formula is deduced? Did the teacher talk about the second derivation method of rotation 27, triangle and trapezoid? Read a book by yourself. Can two identical trapezoids form a parallelogram? It's good to know. Is the base of parallelogram equal to the sum of the upper and lower base of trapezoid? Is the height of parallelogram equal to the height of trapezoid?

Is the area of parallelogram equal to twice the area of trapezoid? Because parallelogram area = base × height? So the trapezoid area = (upper bottom+lower bottom) × height ÷ 28, and the parallelogram area with equal bottom and equal height is equal? Are the areas of triangles with equal bases and equal heights equal? The area of a parallelogram with equal base and equal height is twice that of a triangle. 29, rectangular box into a parallelogram? The circumference is the same? The area becomes smaller. 30. combined graphics? Turn it into a simple figure you have learned? Calculate by addition and subtraction. Unit 6 Statistics and Possibility 3 1, average = total quantity ÷ total number of copies 32. The advantage of the median is that it is not affected by the data being too large or too small? It is more appropriate to use it to represent the overall level of all data. Unit 7 Mathematics Wide Angle 33. Numbers can't only be used to represent quantity and order? It can also be used for coding. 34. Postal code? Made up of six people? The first two figures represent provinces? Municipalities and autonomous regions? 0 5 4 0 0 1 The first 3 digits represent postal areas, and the first 4 digits represent counties? City? The last two digits represent the delivery office. 35.ID code? 18 digits13052197803010019 The penultimate digit of the birth date sequence code in Xingtai County, Hebei Province is used to indicate gender? Does the singular refer to men? Even numbers represent women.