The seventh grade first volume mathematical mind map: rational number
The seventh grade first volume mathematical mind map: the operation of algebraic expressions seventh grade first volume mathematical mind map: linear equation seventh grade first volume mathematical mind map: linear function seventh grade first volume mathematical rational number knowledge points.
(1) positive and negative numbers
1. positive number: a number greater than 0.
2. Negative number: a number less than 0.
3.0 neither positive nor negative.
4. Positive numbers are greater than 0, negative numbers are less than 0, and positive numbers are greater than negative numbers.
(2) rational number
1. rational number: a number consisting of integers and fractions. Include positive integer, 0, negative integer, positive fraction and negative fraction. Can be written as the ratio of two integers. Irrational numbers cannot be written as the ratio of two integers. It is written in decimal form, and the numbers after the decimal point are infinite. For example:? )
2. Integer: positive integer, 0, negative integer, collectively referred to as integer.
3. Score: positive score and negative score.
(3) Number axis
1. Number axis: Numbers are represented by points on a straight line, which is called number axis. Draw a straight line and take any point on the straight line to represent the number 0. This zero point is called the origin, which specifies that the right or upward direction of the straight line is positive; Select the appropriate length as the unit length, so as to take points on the number axis. )
2. Three elements of the number axis: origin, positive direction and unit length.
3. Antiquities: Only two numbers with different symbols are called reciprocal. The antonym of 0 is still 0.
4. Absolute value: the absolute value of a positive number is itself, and the absolute value of a negative number is its inverse; The absolute value of 0 is 0. Compare two negative numbers, and the larger one has the smaller absolute value.
Addition and subtraction of rational numbers
1. Sign first, then calculate the absolute value.
2. Addition algorithm: add the same sign, take the same sign, and add the absolute values. For the addition of different symbols, take the sign of the addend with large absolute value, and subtract the sign with small absolute value from the sign with large absolute value. Two opposite numbers add up to 0. Add and subtract a number with 0, and you still get this number.
3. additive commutative law: a+b= b+ a is added, the position of the addend is exchanged, and the sum is unchanged.
4. The law of addition and association: (a+b)+ c = a +(b+ c) three numbers are added, the first two numbers are added first, or the last two numbers are added first, and the sum is unchanged.
5. a? b = a +(？ B) Subtracting a number is equal to adding the reciprocal of this number.
(5) rational number multiplication (first determine the sign of the product, and then determine the size of the product)
1. The same symbol is positive, different symbols are negative, and the absolute values are multiplied. Any number multiplied by 0 is 0.
2. Two numbers whose product is 1 are reciprocal.
3. Multiplicative commutative law: ab= ba
4. Multiplicative associative law: (ab)c = a (b c)
5. Multiplicative distribution law: a(b +c)= a b+ ac.
(6) rational number division
1. First divide and multiply, then sign, and finally find the result.
2. dividing by a number that is not equal to 0 is equal to multiplying the reciprocal of this number.
3. Divide two numbers, the same sign is positive and the different sign is negative, and divide by the absolute value. Divide 0 by any number that is not equal to 0, and you will get 0.
(7) Stand aside
1. The operation of finding the product of n identical factors is called power. Write one. The result of multiplication is called power, a is called base, and n is called exponent. )
2. The odd power of a negative number is negative and the even power of a negative number is positive; Any positive integer power of 0 is 0.
(8) Mixed operations of addition, subtraction, multiplication and division of rational numbers.
1. Multiply first, then multiply and divide, and finally add and subtract.
2. Operate at the same level, from left to right.
3. If there are brackets, do the operation in brackets first, and then follow the brackets, brackets and braces in turn.
(9) Scientific notation, divisor and significant figures.
Seventh grade, the first volume of mathematical mind map related articles;
1. The contents of the first volume of the seventh grade mathematics handwritten newspaper
2. The first volume of the seventh grade mathematics handwritten newspaper
3. Rational number mind map in junior high school
4. Mind mapping of all units in senior one mathematics.
5. Math Mind Map of Grade One.
6. How to draw a map for your mind?