1, the same problem, different quantities are represented by different letters. For example, if the length of a rectangle is represented by a, the width cannot be represented by a, but by b, otherwise it will cause confusion.

2. In some cases, some letters have specific meanings. For example, when calculating area and perimeter, it is customary to use S for area, C for perimeter and H for height.

3. When using letters to represent numbers, the multiplication sign between numbers and letters and between letters can be recorded as ""or omitted. For example, if you forget the expression of operation rate, please turn it up.

4. When you need to write the unit name when you use letters to represent numbers, if it is in the form of multiplication and fraction, you can write the unit name directly behind it. If+and-appear, please put parentheses, and then write out the unit. For example, the difference between (a+5) meters and 5/a meters.

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Mathematics [English: Mathematics, from ancient Greece μ? θξμα(máthēma)； Often abbreviated as math or maths], it is a discipline that studies concepts such as quantity, structure, change, space and information.

Mathematics is a universal means for human beings to strictly describe and deduce the abstract structure and mode of things, and can be applied to any problem in the real world. All mathematical objects are artificially defined in essence. In this sense, mathematics belongs to formal science, not natural science. Different mathematicians and philosophers have a series of views on the exact scope and definition of mathematics.

Mathematics plays an irreplaceable role in the development of human history and social life, and it is also an indispensable basic tool for studying and studying modern science and technology.

definition

Aristotle defined mathematics as "quantitative mathematics", which lasted until18th century. /kloc-since the 0/9th century, mathematical research has become more and more rigorous, and it has begun to involve abstract topics such as group theory and projection geometry that have no clear relationship with quantity and measurement. Mathematicians and philosophers have begun to put forward various new definitions.

Some of these definitions emphasize the deductive nature of a lot of mathematics, some emphasize its abstraction, and some emphasize some themes in mathematics. Even among professionals, the definition of mathematics has not been reached. Whether mathematics is an art or a science has not even been decided.

Many professional mathematicians are not interested in the definition of mathematics or think it is undefined. Some just said, "Mathematics is done by mathematicians." The three main mathematical definitions are called logicians, intuitionists and formalists, each of which reflects a different school of philosophical thought. Everyone has serious problems, no one generally accepts it, and no reconciliation seems feasible.