Mid-term level test in the first volume of seventh grade mathematics 1. Make your choice (3 points for each small question, 30 points for * * *) 1. If 2km to the east is marked as +2km, then -3 km means (). (a) 3 kilometers east (b) 3 kilometers south (c) 3 kilometers west (d) 3 kilometers north ... The school is 20 kilometers south and the bookstore is north 100. Zhang Ming starts from home, goes north for 50, and then goes north for -70. At this time, Zhang Ming's position is (). (a) At home, (b) At school, (c) At the bookstore, (d) Not at the above place. 3. In the following categories, it must be (). The value of (1) is (). (a)-8(b)-2(c)8 or -2 (d)-8 or 25. If so, then the correct one in the following relationship is (). (a) (b) (c) (d) 6。 In 2007, the Chang 'e-1 satellite of China's lunar exploration project will be launched. Then this distance should be expressed as () by scientific notation (three significant figures are reserved). (a) 3.84× km (B)3.84× km (C)3.84× km (D)38.4× km 7. If it is a cubic trinomial, it is equal to (). None of the above (a)1(b)1(c)-1(d) is true. 8. The following categories are correct: (). (a) (b) (c) (d) 9。 The price of a certain brand of color TV is reduced by 30%. Then the original price of each color TV of this brand is (). (a) 0.7a yuan (B)0.3a yuan (c) yuan (d) 10. Number of columns: 0, 1, 2, 3, 6, 7, 14, 15. Write "2,3" the second time, "6,7" the third time, "14, 15" the fourth time, and so on. Then the last three digits of this series should be the following (). (1) 3 1, 32, 64. 45, 46 seconds, fill in the circle (3 points for each small question, * * * 30 points) 1. The reciprocal is, the reciprocal is; The number whose absolute value is equal to 3 is .2. If m and n satisfy =0, then 3. If any two numbers are not equal to zero, the operation ○+is defined as follows (the meaning of other symbols is as usual): ○+b=, and the value of [(1○+2) ○+3]-[1○+(2 ○+3)] is _ _ _ _ _ _ _ _. 4. Use a calculator to calculate (keep three significant figures): =. 5. Pass on hope. It has _ _ _ _ _ _ _ significant figures, accurate to the right. 6. The coefficient of single item-is, and the number is. 7. If it is a similar term, then =. 8. When =2, the value of the algebraic expression is equal to-17, so when X =- 1, the hundred digits are twice as large as the ten digits, and the single digits are 2 larger than the ten digits. This three-digit number is expressed by algebraic expression. 10. (Lushun) Xiao Wang designed a calculation program with a computer. The input and output data are as follows: input … 1 2 3 4 5 … output … So, when the input data is 8, the output data is. (2).2.(7 points) At that time, find the value of algebraic expression. 3.(7 points) There was once a question: "The calculated value is in it". A student copied ""into ""by mistake, but his calculation result is also correct. Try to explain why.

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