The 6th Primary School "Hope Cup" National Mathematics Invitational Tournament, grade 6, test 1, fill in the blanks (5 points for each small question, ***60 points) 1. (1+0.12+0.23) × (0.12+0.23+0.2. If A is two-thirds of B and B and four-fifths of C, then the ratio of A, B and C is (). 3. If the width of a rectangle is reduced by 20% and the area remains the same, then the length should be increased (). 4. It is known that the sum of three-digit abc and its reverse number cba is 888, and such three-digit ABC has (). During the festival, Xiaoming arranged six colored lights in succession, including two red lights and four green lights. If two red lights are not adjacent, there are () different arrangements (among which "red, green, green and green" and "green, green, red and green" are counted as one). There are more than one hundred students in the sixth grade of a primary school. If you line up in a row of three, there will be one more person; If you line up five people, there will be two more; If you line up seven people, there is one more person. The number of students in this grade is (). 7. As shown in figure 1, if four cubes with side lengths of 1cm, 2cm, 3cm and 5cm are closely attached together, the surface area of the polyhedron obtained is (). 8. Party A, Party B and Party C produce a batch of toys. The quantity produced by Party A is 1/2 of the sum of the quantities produced by Party B and Party C, while the quantity produced by Party B is 1/3 of the sum of the quantities produced by Party A and Party C, and Party C produces 50 toys. There are () pieces of toys in this batch. 9. If a natural number is not equal to 0, its 1/2 is a cubic number and its 1/3 is a square number, then the smallest number is (). 10. In the Nine palace map shown in Figure 2, different Chinese characters represent different numbers, and the sum of each number on each row, column and two diagonal lines is equal. If clock =2 1, Xue =9 and Huan = 12 are known, then the sum of hope, hope and cup is (). 1 1. As shown in Figure 3, triangle ABC and triangle DEC are isosceles triangles, a and e are right-angled vertices, and the shaded part is square. If the area of triangle DEC is 24 square meters, then the area of triangle ABC is () square meters. 12.a and B are 950m apart. Two people, A and B, often return from A to exercise for half an hour at the same time. A walks 40 meters every minute. B running, per minute150m. Then they meet head-on for the first time (), which is closest to B. Second, answer the question (this big question has four small questions, each with 15 and ***60 points). Requirements: write out the calculation process. 13. There is a meadow where the grass grows at the same speed every day. If 14 cows can eat grass for 30 days, 70 sheep can eat grass for 16 days (the amount of grass eaten by 4 sheep in one day is equivalent to that eaten by Niu Yi 1 head of Niu Yi in one day). So, how many days can 17 cows and 20 sheep eat grass? 14. as shown in fig. 4, e, f, g and h are the midpoint of each side of the quadrilateral ABCD, EG and FH intersect at point o, S 1, and S2, S3 and S4 respectively represent the areas of four small quadrilaterals. Compare the sizes of S 1+S3 and S2+S4. 15. 1, 2, 3, how many numbers can be selected at most, ..., 2008, so that the sum of any two selected numbers cannot be divisible by 3? 16. As shown in Figure 5, the lengths of the three circular runways are 0.5km each, and three athletes A, B and C start from the intersection O at the same time and run along the three runways respectively. Their speeds are 4 kilometers per hour, 8 kilometers per hour and 6 kilometers per hour respectively. Q: How many kilometers did three people run from their departure to their first meeting?