Let the addend be x.

The correct answer is x+6.

The wrong answer is x-6.

Then the final answer is less than the correct answer: (x+6)-(x-6)= 12.

History of mathematics development

Mathematics (hanyu pinyin: shùXué；; ; Greek: μ α θ η μ α κ; English: Mathematics comes from the ancient Greek word μ θ η μ α (má th?ma), which means learning, learning and science. Ancient Greek scholars regarded it as the starting point of philosophy and the "foundation of learning". In addition, there is a narrow and technical meaning-"mathematical research". Even in its etymology, its adjective meaning related to learning will be used to refer to mathematics.

Its plural form in English and as the plural form of mathématiques in French +es can be traced back to the Latin neutral plural (Mathematica), which is Cicero's plural from Greek τ α α θ ι α τ κ? (ta mathēmatiká)。

In ancient China, mathematics was called arithmetic, also called arithmetic, and was finally changed to mathematics. Arithmetic in ancient China was one of the six arts (called "number" in the six arts).

Mathematics originated from early human production activities. The ancient Babylonians had accumulated some mathematical knowledge, which could be applied to practical problems. Judging from mathematics itself, their mathematical knowledge is only obtained through observation and experience, and there is no comprehensive conclusion and proof. However, we should fully affirm their contribution to mathematics.

The knowledge and application of basic mathematics is an indispensable part of individual and group life. The refinement of its basic concepts can be seen in ancient mathematical classics of ancient Egypt, Mesopotamia and ancient India. Since then, its development has made small progress. But algebra and geometry at that time were still independent for a long time.

Algebra can be said to be the most widely accepted "mathematics". It can be said that algebra is the first mathematics that everyone has come into contact with since childhood. Algebra, as a discipline to study numbers, is also one of the most important parts of mathematics. Geometry is the earliest branch of mathematics studied by people.