1, MM: it is a unit of length and also a unit of rainfall, abbreviated as mm in English.

2. centimeter: it is a unit of length measurement, equal to one hundredth of one meter.

3. Kilometers: Kilometers, also called kilometers, are units of length and are usually used to measure the distance between two places.

4. Addition: one of the four basic operations, which refers to the calculation of combining two or more numbers and quantities into one number and quantity. The addition symbol is the plus sign (+).

Math language is also difficult for beginners. How to make these words have more accurate meanings than everyday words is also a problem that puzzles beginners, such as open and domain, which have special meanings in mathematics.

6. Mathematical terms also include proper nouns such as embryo and integrability. But these special symbols and terms are used for a reason: mathematics needs accuracy more than everyday language. Mathematicians call this requirement for linguistic and logical accuracy "rigor".

7. Start with the high division of dividend, and try the first digit of dividend with divisor every time. If it is less than the divisor, try the division of the first two digits again.

8. In division with remainder: the minimum remainder is1; The remainder of is divisor minus1; The smallest divisor is the remainder plus 1.

9. Quotient× Divider = Divider Quotient× Divider+Remainder = Divider.

10, estimation of division: In real life, sometimes you don't have to calculate the exact result, but treat some numbers as integer ten, integer hundred and integer thousand close to it, and then calculate them. This calculation is called estimation.

1 1, angle, pentagram, isosceles triangle, equilateral triangle, isosceles trapezoid, square, rectangle, circle and regular polygon are all axisymmetric figures.

12. The characteristic of mathematical calculus is that although there are different methods to solve problems, there must be only one final answer. As long as the calculus is correct, all roads lead to the same goal.

13. Some beautiful theorems in mathematics have the following characteristics: they are easy to be summarized from facts, but their proofs are extremely hidden.

14. Every time you learn a math difficulty, try to explain it to others so that they can understand it. Only when you can explain it clearly can you really understand it.

15, mathematical methods permeate and dominate all theoretical branches of natural science. It has increasingly become the main symbol of measuring scientific achievements.