1. Multiple choice questions (each question 1, * * each question 10) 1. If a and b both represent rational numbers and A+B = 0, then () A.A and b are both 0. B.A, where one b is 0.C.A. B is the reciprocal. 2. The following statement is correct: () A. The sum of a monomial and a monomial is a monomial. B. The sum of a monomial and a polynomial is a polynomial. C. Polynomials and the sum of polynomials are polynomials. D. the sum of algebraic expression and algebraic expression is algebraic expression. 3. The following statement is incorrect (). A. there is the smallest natural number. B. there is no minimum positive rational number. C. there is no largest negative integer. D. there is no maximum non-negative number. 4. If A and B represent rational numbers, and the value of A+B is greater than that of A-B, then () A.A and B are the same symbol. A and b are different symbols. C. B The cube of a positive number is not necessarily greater than itself; C. the square of a negative number is not necessarily greater than itself; D. the cube of a negative number is not necessarily greater than itself. Among the four statements, the number of incorrect statements is () a.0. b. 1. C.2. d.3.7.a stands for rational number, so the relationship between A and -a is () a.a is greater than-A.B. In order to make the obtained equation and the original equation have the same solution, we can multiply the same number B, algebraic expression C, algebraic expression D and 1.9 on both sides of the original equation respectively. There is half a glass of water in the cup, which decreases by 10% on the second day and increases by 65438% on the third day. Compared with the water in the cup on the first day, the water in the cup on the third day turned out to be as much as () A. B. more. C. less. Any quantity is possible. 10. If the speed of the ship itself is fixed in still water, the time taken for a round trip will increase () a.. B. reduce. C. unchanged. D. increase or decrease. Fill in the blanks (each question 1 point, * * * 1 point)1. _ _ _ _. 2.198919902-198919892 = _ _ _. 3. = _ _ _ _ _ _ _ _ _. 6. When x = The weight of salt water is _ _ _ _ _ grams. 9. A batch of parts can be completed in 0/8 days as planned. If the work efficiency is improved after 4 days, it will take _ _ _ _ _ _ _ days to complete half of these parts. 10 days It's 4: 05, and then. The minute hand and the hour hand coincide for the first time. Answers and hints 1. Multiple choice questions 1. C2。 D3。 C4。 D5。 C6。 B7。 D8。 D9。 C 10。 A hint: 1. Let a=2, B =-2, and satisfy 2+. Exclude A. The sum of two monomials x2 is x3-x2 is a monomial, exclude B. The sum of two polynomials x3+x2 and x3-x2 is 2x3 is a monomial, and exclude C. Therefore, D.3. 1 is the smallest natural number, and A is correct. It can be found that the statement that C "has no maximum negative integer" is incorrect. Write an extended natural sequence. It is easy to know that there is no maximum non-negative number and d is correct. So the incorrect statement should be C.5. On the number axis, it is easy to see that there are only -3, -2,-1, 0***4 integers on the right side of-π. Select C.6. From 12 = 65438. 13= 1 shows that statements A and B are correct. From (-1) 3 =- 1, it shows that Ding is also right. The square of a negative number is positive, that is, the square of a negative number must be greater than itself, so the statement that the square of a negative number is not necessarily greater than itself is incorrect. That is, only C 1 is incorrect. Therefore, if you choose B.7. so that a=0, A, B and C can be eliminated immediately, you should choose D.8. to deform the same solution of the equation, which requires that both sides of the equation should be multiplied by numbers that are not equal to 0. So we ruled out a. When we examine the equation X-2 = 0, it is easy to know that its root is X-2 = 0 2. If both sides of the equation are multiplied by an algebraic expression whose roots are x= 1 and x=2, which is different from the original equation, exclude B. If the same algebraic expression is added to both sides of the equation x-2 = 0, the roots of the original equation x=2 should be excluded, so C. In fact, a constant is added to both sides of the equation, and the new equation is the same as the original equation. For d, the constant added here is 1, so choose it. On the third day, the amount of water in the cup is (0.9a) × (1+10%) = 0.9 ×1.1× a; The ratio of the water in the third day cup to the water in the first day cup is that the water in the third day cup is smaller than that in the first day cup, so C. 10. Be chosen. If the distance between two wharves is S, the speed of the ship in still water is A, and the water speed is V, then the round-trip time is V, and (V > v0) the round-trip time is V-V 0 > 0. A+v > a-v so (a+v 0) (a+v) > (a-v 0) (a-v) ∴ t0-t < 0, that is, T0 < T, therefore, the time required to improve the river speed will increase. Choose a.2. Fill in the blanks: 2.198919902-198919892 = (19891990+/kloc-0. = (19891990+1989) ×1= 39783979.3. Due to (2+1) (22+/. (28+ 1)(2 16+ 1)=(22- 1)(22+ 1)(24+ 1)(28+654338(3x 3-5x 2+6x- 1)-(x3-2 x2+x-2)+(-2 x3+3 x2+ 1)= 5x+27。 Note: When A =-0.2 and b=0.04, A2-B = (-0.2) 2-0.04 = 0, and B+A+0.16 = 0.04-0.2+0.16 = 0.