The calendar of the two rivers civilization is very distinctive. In Akkadian era, Sumerians formulated the lunar calendar, taking the moon's profit and loss as the timing standard, and set 29 or 30 days per month, 12 months as 1 year (6 months and 29 days, 6 months and 30 days), and Sumerian stone statues had 354 days per year, and invented the leap month, which was adjusted by setting the leap month. At first, leap was set by experience, then there were 3 leap rules in 8 years and 10 leap rules in 27 years. Divide an hour into 60 minutes. Assyrian period defined the name of today's week and the rule of 7 days 1 week.

In astronomy, stars can already be distinguished from the five planets, and the ecliptic has also been observed.

mathematics

Sumer

Sumerians can also calculate fractions, add, subtract, multiply and divide, and solve quadratic equations with one variable, and invented the decimal method of 10 and the decimal method of 16. They divided the circle into 360 degrees until π was close to 3. Even calculate the area of irregular polygons and the volume of some cones.

Babylon

arithmetic

The ancient Babylonians were skilled calculators, and their calculation programs were realized with the help of multiplication tables, reciprocal tables, square tables and cubic tables. The Babylonian method of writing numbers deserves our attention. They introduced a numerical system based on 60 (hexadecimal), which was also used by Greeks and Europeans for mathematical calculation and astronomical calculation in the16th century. Up to now, the angle, time and other records are still in hexadecimal.

algebra

Babylonians have rich knowledge of algebra, and many clay tablets contain problems of linear and quadratic equations. Their process of solving quadratic equations is consistent with today's solution and formula method. In addition, they also discussed some cubic equations and multivariate linear equations.

On a clay tablet (No.322, purington) from BC 1900 to BC 1600, a number table was recorded, and it was found that there were two groups of numbers in it, namely, the hypotenuse length of a right triangle with an integer length and a right side length, from which another right side length was deduced, that is, the integer solution of the indefinite equation was obtained.

geometry

Babylonian geometry is closely related to actual measurement. They know that the corresponding edges of similar triangles are proportional, and they can calculate the area of a simple plane figure and a simple three-dimensional volume. We now divide the circumference into 360 equal parts because of the ancient Babylonians. The main feature of Babylonian geometry lies in its algebraic properties. For example, the problem of horizontal line parallel to one side of right triangle leads to quadratic equation; Cubic equation appeared when discussing the volume of prism.

The mathematical achievements of ancient Babylon reached a very high level in early civilization, but the accumulated knowledge was only the result of observation and experience, and there was no theoretical basis.

technology

Sumer's technology includes: wheels, saws, leather, bracelets, hammers, saddles, nails, pins, rings, shovels, kettles, knives, spears, arrows, swords, glues, daggers, bags, helmets, boats, armor, quiver, scabbard, boots, slippers, forks and wine making.

Sumerians had three different kinds of boats:

1. Kayak is made of reeds and animal skins.

2. Sailing boats use asphalt to prevent water infiltration.

Wooden boats are sometimes dragged by human or animal power.

Lang.

Sumerian is an isolated language that is not close to any other known language. Attempts to link Sumerian with other languages, especially the Ural-Altaic family, failed. Sumerian is a kind of sticky language, that is, its characters are composed of sticky characters.

Sumerians invented a hieroglyph, which was later developed into cuneiform. This is one of the oldest known human characters. Today, hundreds of thousands of Sumerian objects have been excavated, most of which are carved on clay tablets. These include personal and business letters, remittances, cookbooks, encyclopedias, laws, hymns, prayers, spells and scientific articles including mathematics, astronomy and medicine. Many large buildings, such as large sculptures, are also engraved with words. Multiple versions of many articles have been preserved because they are often copied (for example, as writing exercises). Copying was the only way for people to spread articles at that time. After Sumerians became the rulers of Mesopotamia, Sumerian remained the language of religion and law.

Even experts find it difficult to understand Sumerian writing. Especially the early Sumerian characters are very difficult, because they usually do not contain all grammatical structures.

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