How to judge whether to calculate the surface area or the volume or the sum of edge length in all the application problems of cuboid?

How to judge whether to calculate the surface area or the volume or the sum of edge length in all the application problems of cuboid?

At the end of the title, I will tell you what you are looking for. The surface area is s, and the volume is v. I have never heard of finding the sum of edges

Use two cuboids 6 cm long, 3 cm wide and 1 cm high to make a cube with the smallest surface area. The surface area of the cuboid is______ Square centimeter

(6 × 3 + 6 × 2 + 3 × 2) × 2, = 36 × 2, = 72 (square centimeter); answer: the surface area of this cuboid is 72 square centimeter; so the answer is: 72

Ten practical problems of cuboid and cube in fifth grade mathematics with answers
Who can help me to solve 10 practical problems of cuboid and cube in fifth grade mathematics (with answers)

1. The length of a cuboid is 8.5cm, the width is 4.5cm, and the height is 7cm. What is the sum of the lengths of all its edges?
(8.5 + 4.5 + 7) × 4 = 80cm
2. The total length of the edges of a cube is 60 cm. How many square centimeters is its surface area?
The edge length of the cube is 60 △ 12 = 5cm,
5 × 5 × 6 = 150 square centimeter
3. The volume of a rectangular wooden box is 672 cubic decimeters. The length of the box is 12 decimeters and the width is 7 decimeters. What is the height of the box?
672 ﹣ 12 ﹣ 7 = 8 decimeters
4. The bottom of a rectangular tin bucket is a square with a side length of 3 decimeters, and the height of the bucket is 7.2 decimeters. How many square decimeters of tin is needed to make such a pair of uncovered buckets?
3 × 3 + 3 × 7.2 × 4 = 190.8 square decimeters
5. A rectangular steel plate is 24 decimeters long, 15 decimeters wide and 0.15 decimeters thick. Each cubic decimeter of steel weighs 7.8 kg. How many kg does this steel plate weigh? If the surface of the steel plate is painted, how many square decimeters is the painted area?
24 × 15 × 0.15 × 7.8 = 421.2kg
(24 × 15 + 24 × 0.15 + 15 × 0.15) × 2 = 731.7 square decimeters
6. The edge length of a cube is 1.5 decimeters. How many decimeters is the sum of its edge lengths? How many square decimeters is its bottom area?
1.5 × 12 = 18 decimeters,
1.5 × 1.5 = 2.25 square decimeter
7. A rectangular tea tube, the bottom is square, the side of the square is 7 cm long, 11 cm high, to make this kind of tea tube, at least how many square centimeters of iron sheet?
(7 × 7 + 7 × 11 + 7 × 11) × 2 = 406 square centimeter
8. A cuboid wood, its volume is 240 cubic decimeters, this wood is 2 meters long, 6 decimeters wide, how many decimeters thick?
2 m = 20 decimeters
240 / 20 / 6 = 2 decimeters
9. A rectangular biscuit cone, 20 cm long and 30 cm wide and 30 cm high. If a circle of brand paper is pasted around it (not pasted above and below), how many square centimeters is the area of the brand paper at least?
20 × 30 × 4 = 2400 square centimeter
10. Shengli Road Primary School needs to dig a rectangular sand pit, 4.5m long, 2.4m wide and 0.5m deep
(1) How many square meters does this bunker cover?
(2) How many cubic meters of sand can this bunker hold?
4.5 × 2.4 = 10.8 square meters
4.5 × 2.4 × 0.5 = 5.4 M3
11. A cuboid fish tank, measuring 60cm in length, 30cm in width and 40cm in height from the inside. The water surface in the tank is 5cm away from the tank mouth. How many milliliters of water are contained in the tank?
60 × 30 × (40-5) = = 63000 CC = 63000 ml
12. A cuboid swimming pool, 60 meters long, 25 meters wide and 2.5 meters deep
(1) How many square meters is the area of plastering the four walls and bottom of the swimming pool with cement?
(2) If the water depth of irrigation is 2 meters, 1 cubic meter of water weighs 1 ton, how many tons of water in the swimming pool?
60 × 25 + 60 × 2.5 × 2 + 25 × 2.5 × 2 = 1925 square meters
60 × 25 × 2 = 3000 M3
3000 × 1 = 3000 tons