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The seventh grade mathematics problem book 1
1. Integers and fractions are collectively called rational numbers. 2. inverse number: the inverse number of a is-a.

3. Absolute value: |a|=

4. reciprocal: reciprocal of a (a≠0)

5. Power: the operation of the product of the same factor is called power, the odd power of negative number is negative, and the even power is positive; Any positive power is positive; Any degree of 0 is 0.

6. Rational number operation: operation rules, operation sequence and algorithm.

7. Scientific notation: a×10n (1≤ a <1). Approximation, accuracy, significant figures.

8. An algebraic expression is formed by connecting numbers or letters representing numbers with basic operation symbols (including addition, subtraction, multiplication, division, multiplication and the root to be learned later).

9. The product of numbers and letters is called a monomial.

(1) A single number or letter is also a monomial.

(2) The numerical factor in a single item is called the coefficient of the item.

(3) The sum of the indices of all the letters in the monomial is called the number of times of the monomial.

10. The sum of several monomials is called a polynomial.

(1) In polynomials, each monomial is called a polynomial term, and the term without letters is called a constant term.

(2) Generally, the degree of the term with the highest degree in a polynomial is the degree of this polynomial.

1 1. monomials and polynomials are collectively called algebraic expressions.

12. Items with the same letters and indexes are called similar items, and several constant items are also similar items.

13. Merging similar terms in polynomials into one term is called merging similar terms.

14. The rule of shifting terms: shifting the symbols on one side of the equation to the other side is called shifting terms.

15. Complementary angle: If the sum of two angles is 90, then these two angles are complementary angles. For example, in the right triangle ABC,

∠ A = 90, ∠B = 46 and ∠C = 44, then ∠ B and ∠ C are complementary angles.

16. Complementary angle: If the sum of two angles is 180, then these two angles are complementary angles.

The complementary angle of 17.∠ α is 90-∠α, and that of ∠βis 180-β.

18. The properties of complementary angles: the complementary angles of the same angle or the same angle are equal. The nature of complementary angle: the complementary angle of the same angle or equal angle is equal.

The second exercise

Core learning series (1)

The reciprocal of 1 |2| is _ _ _ _, the inverse of -(-2) is, and the reciprocal is.

2. There are _ _ _ numbers whose absolute value is equal to 3, and they are _ _ _ _ _ _ _ _; There are _ _ _ integers whose absolute value is not greater than 3. They are _ _ _ _ _.

3. In the algebraic expression, the number of:,, and monomials is _ _ _ _ _. If it is a monomial about, and the coefficient is 9 and the degree is 4, then the polynomial is _ _ _ _ _ _ _ _ _.

The antonym of 4 is ()

Eighth century BC-

5. The coefficient and number of monomials are ()

Asian Development Bank.

6.;

7.;

8. Solve the equation: 3 (x-2)+1= x-5 (2x-1).

9. A job is completed by Party A alone for 6 hours, Party B alone for 12 hours, and Party C alone for 18 hours. If A and B do it for 3 hours first, and then B and C do it together, how many hours will it take to complete it?

10. Taxi driver Xiao Li spent an afternoon on the east-west renmin street. If the east is positive and the west is negative, his mileage (in km) this afternoon is as follows:+15, -2, -5, -L,-10, -3, -2.

(1) Let Xiao Li's starting point in the afternoon be O. How far is Xiao Li from the starting point in the afternoon when he sends the last passenger to his destination?

(2) If the fuel consumption of the car is O.35 liters /km, how many liters will Xiao Li * * * consume this afternoon?

Other issues

1 1. Calculation:

Core Learning Series (2)

1. rational number, the largest negative integer is, the smallest positive integer is, the smallest non-negative integer is, and the largest non-positive integer is.

2. if.

Fill in the blanks with ">" or ","

3. If the quadratic term coefficient of a quadratic trinomial about b is -2, the linear term coefficient is -0.5, and the constant term is 3, then the polynomial is _ _ _ _ _ _ _ _ _. The sum of and is _ _ _ _ _.

4. In the following figures, the negative number is ().

BC |-9 years BC ..

5. According to the requirements, use rounding method to approximate 0.050 19 respectively, and the error is ().

A.0. 1 (accurate to 0. 1) B.0.05 (accurate to 1%)

C.0.05 (two significant figures are reserved) D.0.0502 (accurate to 0.000 1)

six ..

seven ..

8. Simplify first, then evaluate

9. Xiaoming painted the room and hired five workers, which took 10 days to finish; Using a coating 150 liter, the cost is 4800 yuan; The painting area is 150 square meters. When the salary is finally settled, there are three schemes:

Scheme 1: according to the workload, each worker will get 30 yuan (1 worker will work for one day);

Option 2: Pay 30% of the painting cost;

Option 3: Pay per square meter for painting area 12 yuan.

Please help Xiao Ming point out which scheme should be chosen to pay the most cost-effective (economical)? (explained by calculation)

10. A food factory took 20 bags of samples from the bagged food produced, and tested whether the quality of each bag met the standard. Excess or deficiency are represented by positive numbers and negative numbers respectively, and are recorded as follows:

Difference from standard mass (unit: gram)

0 1 3 6

Number of bags 1 4 3 4 5 3

(1) Is the average mass of this batch of samples more or less than the standard mass? How many grams more or less?

(2) If the standard mass of each bag is 150g, what is the total mass of sampling inspection?

Other issues

1 1.( 1) Known value. (2) Known value.

Core Learning Series (3)

1. Simplify the following categories:

( 1)-(+2)= ; (2)-(- 15)= ; (3)+[-(-2)]= .

2. If it is known, then _ _ _ _ _ _ _ _. If rational numbers A and B satisfy |a|=5, |b|=4, A3ab.2a ∠ COD B. ∠ AOB = ∠ COD.

C.∠AOB