(2) The first number of each point is expanded to twice its number, and the number of rows remains unchanged.

A(0，4) B(0，2)C(2，3) D(6，5) E( 10，3) F(6， 1) G(8，3)

(3) The first number of each point is unchanged, and the second number is expanded to be twice as large. As above, connect into small fish.

A(0，8) B(0，4) C( 1，6)D(3， 10) E(5，6) F(3，2)G(4，6)

(4) The two numbers of each point are expanded to be twice as many at the same time. As above, connect into small fish.

A(0，8)B(0，4) C(2，6) D(6， 10) E( 10，6) F(6，2) G(8，6)

The third fish is the most similar to the fish in the picture.

2.5/8×3/ 10= 3/ 16 5/8×2= 5/4 5/8× 1/5= 1/8 8/9÷ 1/3= 8/3 8/9÷6= 4/27

8/9÷2/3=4/3

3. Write down the reciprocal of the following numbers

2/7=7/2 5 = 1/5 1/3 =3 1 = 1 15/8 =8/ 15

4. Turn the following ratio into the simplest integer ratio.

8: 12 =2:3 0.25:0.45 =5:9 1/4: 1/8+2: 1

5. Judge whether the following statement is correct.

(1) The reciprocal of the real score must be greater than the real score. ( √ )

(2) The product of a number multiplied by a fraction must be less than the original number. ( × )

(3) The quotient of a number divided by a fraction must be greater than the original number. (× )

(4) The ratio of the number of big bulls to the number of small bulls is 4: 5, that is, the number of big bulls is less than that of calves 1/5. ( √ )

6. How to calculate the following questions as simple as possible?

5/7+5/6+2/7+ 1/6 =(5/7+2/ 7)+(5/6+ 1/6)=2

1/ 15×( 1/3+ 1/ 12) = 1/ 15×5/ 12= 1/36

1/4÷(3-5/ 13-8/ 13)

= 1/4÷(39/ 13-5/ 13-8/ 13)

= 1/4÷2

= 1/8

4/9÷5/6-( 1/6+ 1/3)

=4/9÷2/6

=4/3

7. Three students jump rope. Xiaoming jumped 120, Xiao Qiang jumped 5/8 of Xiaoming's jump, and Liang Xiao jumped 2/3 of Xiao Qiang's jump. How many did Xiao Liang skip?

120× 5/8× 2/3 = 50 (pieces)

8.( 1) Grade 5 students collect 165 cans, and Grade 6 students collect 2/ 1 1. How many cans did the sixth graders collect?

165× (1+2/1) =195 (pieces)

(2) The fourth grade is less than the sixth grade 1/3. How many cans were collected in the fourth grade?

195× (1-1/3) =130 (pieces)

9.( 1) The total output of vegetables in a county last year was 7.2 million Jin, which is 9/ 10 of the total output of vegetables this year. What is the total output of vegetables in the county today?

720 ÷ 9/ 10 = 800 (10,000 kg)

(2) Last year, the total output of vegetables in a county was 7.2 million Jin, less than today110. What is the total output of vegetables in the county this year?

720÷ (1-110) = 800 (ten thousand kilograms)

10.84cm long iron wire forms a triangle, and the length ratio of three sides of the triangle is 3: 4: 5. How many centimeters are there on each of the three sides?

3+4+5 =1284× 2/13 = 21(cm) 84×4/ 12=28 (cm) 84×5/ 12=35.

1 1. Write the simplest integer ratio of the following questions.

(1) The ratio of radius to diameter of a circle is _1:2 _ _ _ _ _ _ _ _.

(2) The radii of two circles are 2cm and 3cm respectively, the ratio of diameters is _ 2: 3 _ _ _ _ _ _ _, and the ratio of perimeters is _ 4: 9 _ _ _ _ _ _ _.

12. Traditional stone mills are used as food processing tools to attract tourists. A tourist walked 300 times along a circle with a radius of1m. How many meters did he walk?

2×3. 14×300= 1884 (m)

13. In some places above 70 north latitude, there is no night for about two months in a year, accounting for16.7 _ _ _ _% of the whole year. Due to the high latitude, the average daily sunshine time in Stockholm, Sweden in July is about 75% of a day, which is _ _18 _ _ _. What percentage of the year is night-free? Use 2÷ 12. 24 hours a day, sunshine time accounts for 75% of 24 hours, and utilization is 24×75%.

14. Fangfang said, "The book was priced in 30 yuan, and the bookstore gave it a 10% discount." "I paid 50% of what Fang Fang paid." "The amount of money I paid is 65438+ 0/3 of the amount of money Fang Fang paid." "I paid 65438+ 0.5 times what Fang Fang paid." What problems can you ask, and will you solve them?

How much did Fangfang spend on books?

30× 90% = 27 (yuan)

(2) How much did the girl in purple spend on books?

27× 1/3 = 9 (yuan)

(3) How much did the boy in green spend on books?

27× 1.5 = 40.5 (yuan)

(4) How much does Fangfang spend more than the girl in purple?

27-9= 18 (yuan)

15. Uncle Wang bought 3,000 yuan of government bonds in 2007 with a fixed term of three years. The annual interest rate of three-year national debt is 5.74%.

(1) Since buying government bonds can be exempted from 5% interest tax, how much interest tax can Uncle Wang be exempted from?

3000×5.74%×3×5%=25.83 yuan.

(2) How much can Uncle Wang get back when it expires?

3000× 5.74 %× 3+3000 = 3516.6 (yuan)

16. In recent years, the proportion of China's oil imports in the total oil consumption has increased year by year. In 2003, the proportion of China's oil imports to the total oil consumption was as follows. Self-produced: 65% imported: 35%

(1) Oil imports are about 9 1 10,000 tons. What is the total consumption?

9100 ÷ 35% = 26,000 (ten thousand tons)

(2) Tens of thousands of tons of self-produced oil?

26000-91000 =16900 (ten thousand tons) or 26000×65%= 16900 (ten thousand tons).

17. The urban air quality in China is gradually improving. Of the 340 cities monitored in 2003, 14 1 city reached the second-class standard. The following is a statistical table for monitoring urban air quality. Meet the second-class standard: 4 1.5% meet the third-class standard: 3 1.8% fail to meet the third-class standard: 26.7%.

(1) How many cities have reached Grade III air quality standards?

340×3 1.8%≈ 108 (pieces)

(2) Understand the air quality in your city and how to improve it.

You analyze it according to the city where you live.