For convenience, when studying factors and multiples, the numbers we refer to are all integers (generally excluding 0).

3. The minimum factor of a number is 1, and the maximum factor is itself.

4. The number of factors of a number is limited.

Numbers like 6,28,496,8128 are called perfect numbers.

6. Among natural numbers, numbers that are multiples of 2 are called even numbers (0 is also even, and numbers that are not multiples of 2 are called odd numbers.

7. Numbers with 0, 2, 4, 6 and 8 are all multiples of 2.

8. Numbers with 0 or 5 are multiples of 5.

9. The sum of the numbers on each digit of a number is a multiple of 3, and this number is a multiple of 3.

10, a number, if only 1 and its own two factors, such a number is called a prime number (or prime number).

1 1, a number. If there are other factors besides 1 and itself, such a number is called a composite number.

12, quality table: 2, 3, 5, 7,1,17, 19, 23, 29, 3 1, 37, 46544.

13. A cuboid is a three-dimensional figure surrounded by six rectangles (in special cases, two opposite faces are squares).

14. In a cuboid, the opposite faces are exactly the same, and the opposite sides have the same length.

15. The lengths of three sides intersecting at a vertex are called the length, width and height of a cuboid respectively.

16. A cube is a three-dimensional figure surrounded by six identical squares.

17, a square can be regarded as a cuboid with equal length, width and height.

18, the total area of six faces of a cuboid or cube is called its surface area.

19, the size of the space occupied by an object is called the volume of the object.

20. unit of volume should be used to measure the volume. The commonly used unit of volume is cubic centimeter, cubic decimeter and cubic meter, which can be written as cm/3, dm/3 and m/3.

2 1, the area at the bottom of a cuboid or cube is called the bottom area.

22. The volume of boxes, oil drums, warehouses and other objects. What can be accommodated is usually called their volume.

23, measuring the volume of liquid, such as water and oil, commonly used unit of volume litres and ml, can also be written as l and ml.

24. The calculation method of cuboid or cube container is the same as that of volume. But measure the length, width and height of the container.

When measuring, dividing things or calculating, it is often impossible to get accurate integer results, which are often expressed by fractions.

25, an object, some objects, etc. Can be regarded as a whole, and this whole is divided into several parts, such a part or parts can be expressed by fractions. A whole can be represented by a natural number 1, usually called the unit "1".

26. Divide the unit "1" into several parts on average, and the number representing one part is called fractional unit.

27, a ÷ b = a/b < b ≠ 0 > (dividend ÷ divisor = dividend/divisor)

28. Fractions with numerator less than denominator are called true fractions. The true score is less than 1.

29. Fractions with numerator greater than denominator or numerator equal to denominator are called false fractions. False score is greater than or equal to 1.

30. Numbers like 1 1/2, 1 3/4 ... are called band scores.

3 1, the basic property of the fraction: the numerator and denominator of the fraction are multiplied or divided by the same number (except 0) at the same time, and the size of the fraction remains unchanged.

32. The common factor of two numbers is called their common factor.

33. Their greatest common factor is called their greatest common factor.

34. Two numbers whose common factor is only 1 are called prime numbers.

35, 4/3 of numerator and denominator have only common factor 1, (numerator and denominator are prime numbers) A score like this is called simplest fraction.

36. Changing a fraction into a fraction equal to it, but with smaller numerator and denominator, is called divisor.

37, 6, 12 and 18 are multiples of 3 and 2 * *, which are called their common multiples. Where 6 is the least common multiple, which is called their least common multiple.

38. Changing different denominator scores into denominator scores equal to the original scores is called total scores. When dividing the numerator by the denominator, several decimal places should be reserved according to the "four-to-five" method as needed.

39. Use the denominator to add and subtract fractions. The denominator remains the same, and only the numerator is added and subtracted.

40. In a set of data, the number with the highest frequency is the pattern of this set of data.

4 1, mode can reflect the concentration of a set of data.

42. In a set of data, there may or may not be multiple patterns.

43. The two-track statistical chart can clearly analyze the differences between the two sets of data.