1. One day, Thales saw people reading the notice, and he went up to have a look. The initial notice said that Pharaoh wanted the smartest person in the world to measure the height of the pyramid. Thales is going to Pharaoh. Pharaoh asked Thales what tools he used to measure the pyramids. Thales said that it is strange that everyone only uses a stick and a ruler. He put the stick next to the pyramid, and when the shadow of the stick was as long as the stick, he measured the pyramid. He measured the length of the shadow of the pyramid and half the length of the bottom of the pyramid. Add these two lengths to get the height of the pyramid. Thales is really the smartest man in the world. He can easily measure the height of the pyramid without climbing to the top.

2. About 1500 years ago, European mathematicians did not know how to use "0". They use Roman numerals. Roman numerals are symbols representing numbers, which are combined to represent different numbers according to certain rules. When using this number, the number "0" is not needed.

At that time, a scholar of the Roman Empire discovered the symbol "0" from Indian notation. He found it very convenient to use "0" for mathematical operation, and he was very happy. He also introduced the Indian method of "0" to everyone. After a while, it was known by the pope at that time. At that time, it was the Middle Ages in Europe. The power of the church was very strong, and the power of the pope far exceeded that of the emperor. The Pope was very angry. He rebuked that the sacred number was created by God, and there was no such monster as "0" in the number created by God. Anyone who wants to introduce now is blasphemous! So the Pope ordered the scholar to be arrested and tortured, and his ten fingers were tightly clamped with a clamp, so that his hand was disabled and he could no longer write with a pen. In this way, "0" was banned by the ignorant and cruel Pope.

However, although the use of "0" is forbidden, Roman mathematicians still use "0" secretly in mathematical research regardless of the ban, and still make a lot of mathematical contributions with "0". Later, "0" was finally widely used in Europe, but Roman numerals were gradually eliminated.