The reciprocal of 1 and rational number13 is (b)
1 3 (B)- 1 3 (C)3 (D)-3
2, in 0,-1, 1, 2, the smallest number is (b).
0 (B)- 1 (C) 1 (D)2
3, the following calculation, the correct is (c)
a 、(-2)-(-5)=-7 B 、(-2)+(-3)=- 1
c 、(-2)×(-3)=6 D 、(- 12)÷(-2)=-6
4, the following judgment is wrong (B)
(a) The absolute value of any number must be positive; (b) The absolute value of negative numbers must be positive;
(c) The absolute value of positive numbers must be positive; (d) The absolute value of any number is not negative;
5. Press the key 1 6-7 = The result displayed on the calculator is (b).
a、 1 B 、- 1 C、3 D 、-3
6. The approximate positions of real numbers A, B and C on the number axis are as shown in the figure, so the size relationship of A, B and C is ().
A, a<b<c B. a<c<b C. b<c< cannot be determined.
7. Subtract the number n by 3 and expand it by 5 times. The final result is ().
A.n-3×5b . 5(n-3)c n-3+5n d . 5n-3
8. The following:, -25,,, The number of monomials is ()
a，4 B，3 C，2 D， 1
The square root of 9 is ()
a、4 B、4 C、2 D、2
10, the following statement is true ()
A, the precision of divisor 1.70 is the same as that of divisor 1.7;
B, the precision of divisor 500 and divisor 500 is the same;
C. The approximate value of 4.70× 104 is a number accurate to a hundred, and it has three significant figures, namely 4, 7 and 0;
D. The approximate value of 24.30 is a number accurate to 100, and it has three significant figures, namely 2, 4 and 3;
Fill in the blanks (*** 10 small questions, 3 points for each question, ***30 points)
1 1, contrast size: ①–14 _ _ _ 0; ② – ; ③3_____|–5|;
12、 =_____________;
The reciprocal of 13 and -2007 is _ _ _ _, the cube root of _ _ _ _ _ _ _, and the absolute value of -2 is _ _ _ _ _ _ _ _ _ _;
14, the number whose absolute value is equal to 3 is _ _ _ _ _ _ _ _;
There are _ _ _ _ natural numbers with 15 less than 3. 14;
16. According to estimates, the direct economic loss caused by desert in China exceeds 54 million yuan each year, which is expressed as _ _ _ _ _ _ million yuan by scientific notation;
17. If and are similar items, AB = _ _ _ _ _ _ _ _
18. Given that the algebraic expression X+2Y has a value of 3, the algebraic expression 2x+4Y+ 1 has a value of;
19. Write two irrational numbers whose sum is 8.
20. There are 2007 black triangles "▲" and "△ * * *", which are arranged as follows according to certain rules:
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲ ... and then the black triangle;
Iii. Answering questions (***40 points)
2 1, (6 points) Fill in the following figures in the corresponding brackets indicating the set.
-5,π, , , ,-0.2, 1.6, ,0, 1. 10 100 1000 1……
Integer {...}
Negative score {...}
Irrational number {...}
22.(8 points) Calculation (2 points for Item ①, 3 points for Item ② and ③)
①、-7+ 16; ② (The result is accurate to 0. 1)
③、
23.(6 points) There are three sets of figures below. Please design an appropriate operation scheme so that the operation result of each group number is 10.
( 1) 1 5 5 9= 10 (2)3 3 3 3= 10 (3) 1 9 9 9= 10
24.(6 points) Simplify first and then evaluate:
, where x =- 1 and y = 2.
25.(6 points) During the "October 1st" Golden Week, the number of tourists in Wuzhen Scenic Area during the 7-day holiday is as follows.
(A positive number means there are more people than the day before, and a negative number means there are fewer people than the day before)
Date: 10, 10,10,2,10,3,10,4,10,5,10,6.
Digital change
Unit: 10,000 people+1.6+0.8+0.4-0.8+0.6-1.2.
(1) Please decide which of the seven days has the most tourists. When is the least number of tourists? There are thousands of them different.
(2) If the number of tourists on September 30th is 20,000, what is the average daily number of tourists in these seven days?
26.(8 points) Read the following materials before answering the following questions.
Material: generally, n identical factors are multiplied:. For example, 23 = 8. At this time, 3 is called the logarithm of 8 based on 2, and is recorded as. Generally, if, then n is called the logarithm with base B, and 4 is called the logarithm with base 3 of 8 1.
Question: (1) Calculate the value of the following logarithm.
;
(2) What is the relationship between the three numbers 4 in (1) and16,64? What kind of relationship are you satisfied with?
(3) Can you draw a general conclusion from the result of (2)? Agree 48| Comment (26)