They are: 8, 18, 28, 38, 48, 58, 68, 78, 80, 8 1, 82, 83, 84, 85, 86, 87, 88, 89, 98.

Note that there are two eights in 88, so it is obvious that a * * * has 20 eights between 1 and 100.

The origin of Arabic numerals:

In the 3rd century AD, the ancient Indian scientist Baghdad invented Arabic numerals. The oldest meter is about 3 at most. In order to imagine the number "4", it is necessary to add 2 and 2. 5 is 2 plus 2 plus 1, and 3 is 2 plus 1. Five fingers in handwriting represent the number 5, and ten fingers in both hands represent the number 10, which is probably too late. This principle is actually the basis of mathematical calculation.

Rome's count is only numbers within V (that is, 5), and numbers within X (that is, 10) are composed of V (5) and other numbers. ⅹ is a combination of two ⅴ, and the same digital symbol has different quantities according to its position relationship with other digital symbols.

In this way, the concept of digital position began, and this important contribution in mathematics should be attributed to the ancient residents of the two river basins. Later, the ancients improved on this basis and invented the symbols 1, 2, 3, 4, 5, 6, 7, 8, 9, 0 to represent numbers, which became the basis of counting.

Two hundred years later, the Arabs unified under Islam conquered the neighboring nationalities and established the Arab Empire from India in the east to Spain in Africa in the west. Later, this great Islamic empire split into two countries, East and West.

Because the kings of these two countries reward culture and art, the capitals of both countries are very prosperous, especially Baghdad, the eastern capital. Greek culture from the west and Indian culture from the east are gathered here. Arabs understand and digest two cultures, thus creating a unique Arab culture.

About 700 years ago, the Arabs conquered Punjab, and they were surprised to find that the mathematics in the conquered area was more advanced than theirs. So I tried to absorb these numbers.

In 77 1 year, mathematicians in northern India were captured in Baghdad, Arabia, and forced to teach local people new mathematical symbols and systems, as well as Indian-style calculation methods. Because Indian numerals and Indian counting methods are simple and convenient, their advantages far exceed other calculation methods. Arab scholars are willing to learn these advanced knowledge, and businessmen are willing to do business in this way.

Later, Arabs introduced this figure to Spain. In 10 century, it was spread to other European countries by Pope Gelber Auriac. Around 1200, European scholars formally adopted these symbols and systems.

In the13rd century, at the initiative of Fibonacci, a mathematician in Pisa, Italy, ordinary Europeans also began to adopt Arabic numerals, which was quite common in the15th century. At that time, the shape of Arabic numerals was not exactly the same as that of modern Arabic numerals, but they were relatively close. Many mathematicians have made great efforts to write them as 1, 2, 3, 4, 5, 6, 7, 8, 9, 0.