Two figures that are folded in half and completely coincident along the center line are called symmetrical figures.

2.？ The distance between the corresponding point and the symmetry axis is equal.

3.？ Connecting lines connecting corresponding points are perpendicular to each other.

4.？ 2 and 6 are factors of 12. 12 is a multiple of 2 and also a multiple of 6.

5.？ For convenience, when studying factors and multiples, we refer to integers (generally excluding 0).

6.？ The smallest factor of a number is 1, and the largest factor is itself.

7.？ The number of factors of a number is limited.

8.？ The minimum multiple of a number is itself, and there is no maximum multiple.

9.？ The multiple of a number is infinite.

10.？ 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. 1 1.？ Numbers in units of 0, 2, 4, 6 and 8 are all multiples of 2.

12.？ A number with 0 or 5 is a multiple of 5.

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

14.？ If a number has only 1 and its own two factors, it is called a prime number (or prime number).

15.？ A number is called a composite number if it has other factors besides 1 and itself.

16.？ 1 is neither prime nor composite.

17.？ Quality table: 2, 3, 5, 7, 1 1, 13, 17, 19, 23, 29, 3 1, 37, 4/kloc.

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

19.？ In a cuboid, the opposite faces are exactly the same, and the opposite sides are equal in length.

20.？ The length of three sides intersecting at a vertex is called the length, width and height of a cuboid.

2 1.？ A cube is a three-dimensional figure surrounded by six identical squares.

22.？ A cube can be regarded as a cuboid with equal length, width and height.

23.？ The total area of six faces of a cuboid or cube is called its surface area.

24.？ The surface area of a cuboid = (length× width+length× height+width× height) ×225. The uncovered surface area of a cuboid = length× width+(length× height+width× height) ×226. Surface area of cube = side length × side length ×6? (Any area ×6)

27.？ Surface area of uncovered cube = side length × side length ×528. The space occupied by an object is called its volume.

29.？ The unit of volume is used to measure the volume. The commonly used unit of volume is cubic centimeter, cubic decimeter and cubic meter, which can be written as cm3 and dm3? ，m3？ 30.？ The area at the bottom of a cuboid or cube is called the bottom area. 3 1.？ Cuboid volume (volume) = length× width× height V=abh? 32.？ Cube volume) = side length × side length × side length V=3a33. Cuboid (or cube) volume = bottom area × height V=sh34. 1dm3= 1000? cm3？ 1? m3？ = 1000? dm335. 1L= 1000ml？ 1L= 1？ dm3？ 1ml= 1？ Cm336。 The volume of boxes, oil drums, warehouses and other objects. What can be accommodated is usually called their volume. 37.？ The volume of liquids, such as water and oil, is usually measured in liters and milliliters, and can also be written as L and ml. 38.？ The calculation method of cuboid or cube container is the same as that of volume. But the length, width and height are measured from the inside of the container. 39.？ When measuring, dividing things or calculating, it is often impossible to get accurate integer results, so it is often expressed by fractions. 40.？ An object, some objects, etc. It can be regarded as a whole, and this whole can be divided into several parts on average, and such one or several parts can be expressed by fractions.

4 1.？ A whole can be represented by a natural number 1, usually called the unit "1"42. Divide the unit "1" into several parts on average, and the number representing one part is called fractional unit.

43.a ÷ b = ab≠044。 ? Fractions with numerator less than denominator are called true fractions. The true score is less than 1. 45.？ Fractions with numerator greater than denominator or numerator equal to denominator are called false fractions. False score is greater than or equal to 1. Like what? ,? ..... such a score is called a score.

46.？ The basic nature 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.

47. 1, 2,4 are the common factors of 16 and 12, which are called their common factors. Where 4 is the greatest common factor, which is called their greatest common factor. 48.？ Two numbers whose common factor is only 1 are called prime numbers.

49.？ The numerator and denominator have only the common factor 1 (both numerator and denominator are prime numbers). Scores like this are called simplest fraction. 50.？ Changing a fraction into an equal fraction with smaller numerator and denominator is called divisor. 5 1.？ 6、 12、 18 & amp； #8226; & amp#8226; & amp#8226; & amp#8226; & amp#8226; & amp#8226; Is a multiple of 3 and 2***, which is called their common multiple. Where 6 is the least common multiple, which is called their least common multiple.

52.？ Dividing 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 method of "rounding" as needed.

53.？ If the simplest fraction can be reduced to a finite fraction, then its denominator only contains prime factors 2 and 5.

54.？ Add and subtract fractions with the denominator, the denominator remains the same, and only the numerator is added and subtracted. Fractions with different denominators must be divided before addition and subtraction. 55.？ The calculation method of fractional addition and subtraction is the same as that of integer addition and subtraction.

56.？ The commutative law and associative law of integer addition are also applicable to fractional addition.

57.？ In a set of data, the number with the highest frequency is the pattern of this set of data. Patterns can reflect the concentration of a set of data.

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

59.？ The two-track statistical chart can clearly analyze the differences between the two groups of data.