Mathematical problem solving

1, 1.2 liters = (12) cubic centimeters 6.25 square meters = (6) square meters (25) square decimeters 2.8 cubic meters =(28) cubic decimeters 5 square meters 4 square decimeters =( 5.4) square meters

2, starting from point on the number axis, move three unit lengths to the right to point A. Move 6 unit lengths to the left from point to point B. The number represented by point B is (-6 )

3. Compare the size, and fill in """"or "=" in ○.

>-6-3 < 1-.8 <-2-7 <-5

4. The weather forecast published in the newspaper one day said that the temperature today is -1℃~4℃, which indicates that the highest temperature in the day is (4℃) and the lowest temperature at night is (-1℃); The temperature difference between day and night is (14 C).

5. A cylinder has a base area of 19 square centimeters and a height of 12 centimeters, and the volume of a cone with the same base height as this cylinder is (19x12=228 cubic centimeters).

6. The volume of a cone is 24 cubic centimeters, the bottom area is 8 square centimeters, and its height is (3 centimeters).

7. The lateral area of a cylinder is 1.56 square decimeters, the height is 2 decimeters, and its volume is (6.28 cubic decimeters).

8. A cylinder and a cone have the same base height, and the sum of their volumes is 48 cubic decimeters, so the volume of the cone is (12) cubic decimeters.

9. Immerse a cone in a cylindrical container with a bottom area of 3 square centimeters, and the water level rises by 4 centimeters. The volume of this cone is (12) cubic centimeters.

1. Use a rectangular piece of paper with a length of 4.5 decimeters and a width of 2 decimeters to form a cylindrical paper tube, and its lateral area is (9) square decimeters.

11. Cut a cone-shaped wood with a bottom circumference of 31.4 decimeters vertically along the bottom diameter, increase the surface area by 3 square decimeters, and the volume of the cone is (235.5) cubic decimeters.

12. Divide the bottom of a cylinder into several sectors on average, and then cut it to form an approximate cuboid, with the surface area increased by 2 square centimeters. It is known that the height of a cylinder is 2 cm and the volume of a cylinder is (157) cubic centimeters.

second, true or false. (8 points)

1. There are only 4 negative numbers between and -5. (error)

2, 12℃ (+12℃) above zero and 12℃ (-12℃) below zero are two quantities with opposite meanings. (error)

3. When the radius of the bottom surface of the cylinder is doubled, the volume of the cylinder is quadrupled. (Correct)

4. If the height of a cylinder is equal to the circumference of its bottom surface, then its side development diagram is a square. (Correct)

5. A cuboid with equal base and equal height has the same volume as a cylinder. (Correct)

6. A cylindrical glass can hold 1 cubic decimeter of water, so we say that the glass volume is 1 liter. (correct)

7. If the volume of a cone is equal to the volume of a cylinder, the cylinder and the cone must have the same base and the same height. (error)

8. If a cone has the same height as a cuboid, then the volume of the cone is equal to that of the cuboid. (error)