1, the number a is divided by the number b, the quotient is 5, and the remainder is 2. If a and b are simultaneously expanded by 10 times, the quotient is 5, and the remainder is 2.

2, a cuboid, the length is increased by 2 times, the width and height are unchanged, and the volume is expanded by (2) times.

3. There are 20 cents, 50 cents and 1 yuan RMB, and there are (15) ways to take out 2 yuan.

4. There is a trapezoidal plate, the upper bottom is 0.6m more than the lower bottom, the upper bottom1.8m, and the height is 0.9m less than the lower bottom. The area of this board is (0.9).

If a piece of wood is sawed into three sections, it takes Xiaoming 6 minutes, and his father saws wood three times as fast as Xiaoming. It will take Dad (4) minutes to saw this piece of wood into 5 pieces.

6. A rope is wound around a tree. If it is wound around 10, there are still 3 meters left; if it is wound around 12, there are still 3 meters left, then it is wound around 8 times, and there are (9) meters left. 9. On the map of 1: 2000, the distance between A and B is 36 cm, and the actual distance between A and B is (720) meters.

10, the average of five numbers is 20. If one number is changed to 4, the average of five numbers is 18, and the changed number is (6.5).

1 1, there are 249 flowers, which are circularly arranged in the order of 5 red flowers, 9 yellow flowers and 13 green flowers, and the last flower is (yellow flowers). Among these 249 flowers, there are (1 17) green flowers.

13. Triangle and parallelogram have the same base and area. The height of parallelogram is 6 cm, and the height of triangle is (12).

14, scientists conducted an experiment, which was recorded every five hours. When making the twelfth record, the hour hand of the wall clock just pointed.

To 9, when the first record is required, the hour hand points to (9).

4. From A to B, it is downhill. Xiaohua goes uphill 60 meters per minute and downhill 100 meters per minute. It takes 8 minutes for a floret to go from A to B than from B to A. How many meters is there between A and B?

(100-60)*8=320 (m)

5. The cost of 1.200 exercise books is 0.25 yuan, and the profit price is 40%. After 80% of them are sold, the remaining exercise books are sold at a discount, with a predetermined profit of 86%. How much discount was given to the rest of the exercise books when they were sold?

0.25* 1200=300 (Yuan) 1200*80%=960 (Ben) 300*( 1+40%)=420 (Yuan) 420 * 86% = 366544.