1, Xiao Fang is a carpenter, but he is arrogant. One day, the master asked him, "The table has four corners. I cut off one, how many are left? " Xiao Fang said 4- 1=3, three. The master told him that there were five people.

2. Xiao Ming asked: Why are wheels round? Xiao Qiang drew a circle with a compass and said, "We measured the distance from any point on the circumference to the center of the circle and found that they were all equal. This is called radius. Make the wheel round, and the distance between the axle and the ground is always equal to the radius of the wheel, so that the wheel can roll smoothly on the ground. If the wheel is square or triangular, and the distance from the rim to the center of the circle is not equal, the car will vibrate up and down when walking. Therefore,