3, - 6,9, - 12 ··, - 20042007, - 2010 the 100th number is? The sum of this column is?
Regardless of the sign, the original sequence becomes 3, 6, 9, 12 , 2004, 2007, 2010 this is an arithmetic sequence, the first term is 3, the tolerance is 3, so A100 = 3 + 99 * 3 = 100 * 3 = 300, odd term is positive, even term is negative, so the sum of the 100th number is - 300 sequence = (3-6) + (9-12) + +(2001-2004)+(2...
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- 1. 3,-6,9,-12… -20042007, - 2010 to find the sum of this column
- 2. 3, - 6,9, - 12 , - 2004, 2007, 2010, complete the following questions: (1) write the 100th number in this column; (2) Find the sum of this column
- 3. Known 3, - 6,9,12 Complete the following questions: find the sum of this column?
- 4. Given 3, - 6,9, - 12... - 20042007 write the 100th number in this column? Find the sum of the number in this column?
- 5. Half, two fifths, three tenths, four seventeen, five twenty-six. What's the next number? The nth?
- 6. Half, two fifths, three tenths, four seventeen
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- 8. It is known that the density of bricks is 1.5 × 103 kg / m3. The walls of a house are built with bricks of 25 cm in length, 12 cm in width and 6 cm in thickness. If the total area of the internal and external walls of the house is 720 square meters and the thickness of the wall is 25 cm, the construction of the house will need bricks______ If the car can carry 4 tons at a time, it should be pulled at least______ It's only three times before you can pull these bricks
- 9. How many bricks does a house that is 10 meters long, 3 meters wide and 2 meters high need Please write down the formula if possible
- 10. Piggy's room area is 60 square meters. How many such floor tiles do you need? (the upper bottom of trapezoid is 1 meter, the lower bottom is 3 meters, and the height is 2 meters)
- 11. The number of columns in the order of law is: - 1,3, - 5,7, - 9, 11. According to this rule, what is the 20th number in this column and what is the nth number What's the 20th book in this column
- 12. Write three fractions of equal size with nine numbers 1, 2, 3, 4, 5, 6, 7, 8 and 9. (each number can only be used once). For example: 36 = 714 = 2958
- 13. Use 9 numbers 123456789 to write three equal fractions. Each number can only be used once
- 14. 1 + 0 * 9 = 1,2 + 1 * 9 = 11,3 + 12 * 9 = 111 until 9 + 123456789 * 9 = 111111111 is there any rule
- 15. According to 123456789 * 9 = 1111111101, make the following formula answer 123456789*18=?123456789*36=?123456789*54=?123456789*72=? 123456789*27=?123456789*45=?123456789*63=?123456789*81=?
- 16. Observe carefully, find out the rule, and then fill in the number 111111111 △ 9 = 123456789 222222222 △ 18= Observe carefully, find out the law, and then fill in the number 111111111÷9=123456789 222222222÷18=123456789 333333333÷27=123456789 ( )÷36=123456789 777777777÷( )=( ) ( )÷( )=( )
- 17. 1 ,3,1 ,4 ,9,1 ,8,( ) A 18 B 27 C 36 D12
- 18. The sum of the side length of a square and the width of a rectangle is 20 cm, the perimeter of a square is one and one third of the perimeter of a rectangle, and the width of a rectangle is 4 / 5 of the length. How much is the area of the square and rectangle and the fact How much is the area sum of square and rectangle?
- 19. 1. The arc length of the sector is a, the radius is r, the sector area is 2, and the concentric angle of the sector is 150 degrees. Then the area of the sector is equal to the area of the circle where the sector is located 3. If the radius of circle O is 4cm and one of the arcs is 2cm long, what is the central angle of the arc
- 20. Find the equation of the circle with n (1,3) as the center and tangent to the line 3x-4y-7 = 0