Mathematical error-prone title

1. A non-zero natural number less than 20, () is an even number, () is an odd number, but not a prime number.
2. In (), when it is (), it can be turned into an integer.
3. On a 150 cm length of rope, from left to right and dot every 6 cm; 5 cm intervals from right to left and dot. Then the rope at a point along the cut, the result is a length of 1 cm with a rope () root.
4. Known A = 2. 3 × × ×. 7. 5, b = 2 × 2 × ×. 5. 3, A and b to have a common factor ().
5. = 64 cm2 () square decimeter. (Fill in the score)
6. A rectangular metal capless tank, a length 2m, width is 55cm, high or 1.2m. How many square meters of metal needs?
7. 10 a section of the sawn timber, the common six minutes. Each saw an average period of use () minutes.
8. Then take the long 8cm, width 5cm, 4cm high into the long rectangular 16cm, width 8cm, 6cm height of the box, can hold up to how many? How loaded?
9. 4 packets of salt, three packs 500 grams per pack, a pack other than 500 grams, but I do not know or light heavier than 500 grams. He said at least a few times?
10. Xiaogang build a three-dimensional graphics, it is seen from the front and right side, then he requires a minimum of () a small cube.