Miancheng Middle School Seventh Grade Mathematics (Part 1) Midterm Exam Paper 2012.11 1. Multiple choice questions: (2 points for each question, ***16 points) 1. The number of seats in the "Bird's Nest" for the 2008 Beijing Olympic Games is 91,000. This number is notated in scientific terms.

The method is expressed as ( ) A. 0.91×105 B. 9.1×104 C.91×103 D. 9.1×103 2. The following statement is correct ( ) A.–2 is a monomial B. –a represents a negative number C.

The coefficient is D. x+ +1 is a polynomial 3. Which of the following calculations is correct ( ) A. B. C. D.4.

Among the following groups of numbers, the ones that are equal are ( ) A. and –16 B. and –(–3) C. and D. –1 and (–1)n5. If the sum of a polynomial and is equal to, then this polynomial is (

)A.

B.

C.

D.

6.

If and, then it is equal to ( ) A.

4B．

10C.

±4D.

4 or 107.

If the polynomial about x does not contain quadratic terms, then m is equal to ( ) A.2 B.-2 C.3 D. -38.

As shown in the figure, a square with a side length of cm is cut from a square piece of paper with a side length of (a + 4) cm, and the remaining part is cut along the dotted line to form a rectangle (no overlap and no gaps), then the area of ??the rectangle is ( )

.A.

B.

C.

D.

2. Fill in the blanks: (Each question is 3 points, ***15 points) 9. The rational number whose square is 9 is ________. 10. The coefficient of the monomial - is _______, and the degree is ________. 11. If 3x2ym+n

If they are the same term as -2x2my3, then m-n=________.12. The approximate number 2.13 is accurate to _________ digits.13.

It is known that the value of x2-4x+6 is 9, then the value of 6-3x2+12x is ________. 3. Calculation questions: (5 points for each question, ***25 points) 14. 15. -0.252÷16

. 17.18．

When Xiao Ming calculated, he did it like this: == -12-18+8=-22. Is he doing it right?

If it is not correct, please write down the correct calculation process.

4. Answer questions: (Questions 19-24, 6 points for each question, 8 points for Question 25) 19. It is known that the sum of and is a monomial, find the sum of these two monomials.

20. Simplified evaluation: , where 21. is known, try to find the value.

22. It is known that Xiao Ming’s age is years, Xiao Hong’s age is several times younger than Xiao Ming’s age, and Xiao Hua’s age is many years older than Xiao Hong’s age. Find the sum of the ages of these three classmates.

23. Explore the rules: (1) Observe the following sequence of numbers: 3, 6, 10, 15, 21,... Please find out the order of the numbers and fill in the blanks according to this rule.

The 9th number is __________, and the nth number is ____________. (2) Given a column of numbers: 1, ―2, 3, ―4, 5, ―6, 7,... Arrange this column of numbers into a triangular number

Array: 1 -2 3 -4 5-6 7 -8 9 -10 11 -1213-14 15... ...arrange according to the above rules, then the fifth number from the left in the 10th row is the sum of the numbers in the 100th row

For ____________.24.

Students all know that |3-(-2)| represents the absolute value of the difference between 3 and -2. Its meaning on the number axis is the distance between the point representing 3 and the point representing -2.

Try to explore: (1) Find |3-(-2)|=______.