Algebraic expression 1 Algebraic expression: monomials and polynomials are collectively called algebraic expressions.
2. Monomial: The formula consisting of the product of numbers and letters is called monomial. A single number or letter is also a monomial.
3. coefficient; In the monomial, the numerical factor is called the coefficient of the monomial.
4. Times: The sum of the indices of all the letters in the monomial is called the times of this monomial.
5. Polynomial: The sum of several monomials is called polynomial.
6. Term: Each monomial that constitutes a polynomial is called a polynomial term.
7. Constant term: the term without letters is called constant term.
8. Degree of Polynomial: In a polynomial, the degree of the term with the highest degree is called the degree of this polynomial.
9. Similar terms: In polynomials, terms with the same letters and the same index of the same letters are called similar terms.
10. Merging similar items: Merging similar items in polynomials into one item is called merging similar items.
Rational number 1. The concept of rational number: positive integer, 0, negative integer, positive fraction and negative fraction are collectively called rational numbers; Number axis and origin: Numbers are represented by points on a straight line, which is called number axis. Any point on this line represents 0, which is called the origin. The distance from this point to the left or below the origin is represented by a negative number, and the distance from this point to the right or above the origin is represented by a positive number. The two numbers represented by two points with opposite and equal distances from the origin on the number axis are opposite numbers, and the distance from point A to the origin on the number axis is called the absolute value of this number.
2. Addition and subtraction of rational numbers: two numbers with the same sign are added, the sign is unchanged, and the absolute value is added; Add two numbers with different signs and different absolute values, take the sign of the addend with larger absolute value, subtract the absolute value of the smaller number from the absolute value of the larger number, and add two numbers with opposite numbers to get 0; One rational number MINUS another rational number is equivalent to adding the reciprocal of this number;
3. Multiplication and division of rational numbers: two numbers with the same sign are multiplied, the same sign is positive, and the different sign is negative. The product of multiplication is the product of their absolute values, division is the dividend multiplied by the reciprocal of the divisor, and the divisor cannot be 0; Two numbers whose product is 1 are reciprocal, and 0 has no reciprocal; Multiplication turnover rate and combination rate of integers are also applicable to rational numbers; The operation of finding the product of n identical factors is called power, and the result of power is called power. In the n power of a, a is called the base and n is called the exponent. Write a ∧ n;
4. Mixed operation of rational numbers: multiply first, then multiply and divide, and finally add and subtract; Operation at the same level, from left to right; If there are brackets, do the operation in brackets first, and then follow the brackets, brackets and braces in turn;
5. Scientific notation: A number greater than 10 is expressed as a× 10∧n, where a is greater than or equal to 1 less than 10, and n is a positive integer, which is called scientific notation.
Angle 1. Angle: An angle is a geometric object composed of two rays with a common endpoint.
2. Angle measurement unit: degrees, minutes and seconds.
3. Vertex: An angle consists of two rays with a common endpoint, and the common endpoint of the two rays is the vertex of the angle.
4. Angle comparison:
The angle (1) can be regarded as a ray rotating around its endpoint.
(2) Flat angle and fillet: A ray rotates around its endpoint. When the starting edge and the ending edge are on a straight line, the angle formed is called a straight angle. When it coincides with the starting edge again, the angle formed is a fillet. A right angle is equal to 108 degree, a rounded corner is equal to 360 degree, and a right angle is equal to 90 degree.
(3) bisector: A ray drawn from the vertex of an angle divides this angle into two equal angles, and this ray is called the bisector of this angle.
5. Complementary angle and complementary angle:
(1) Complementary angle: If the sum of two angles is 90 degrees, then these two angles are called complementary angles, which is called "complementation" for short.
Property: The complementary angles of equal angles are equal.
(2) Complementary angle: If the sum of two angles is 180 degrees, these two angles are called "complementary angle" or "remainder" for short.
Property: The complementary angles of equal angles are equal.
Parallel lines 1. In the same plane, if two straight lines have no intersection point, then the two straight lines are parallel to each other, which is recorded as: a ∨ b.
2. Parallelism axiom: After passing a point outside a straight line, there is one and only one straight line parallel to this straight line.
3. If two straight lines are parallel to the third straight line, then the two straight lines are parallel to each other.
4. The method of judging that two straight lines are parallel:
(1) Two straight lines are cut by the third straight line. If congruent angles are equal, two straight lines are parallel. To put it simply: the same angle is equal and two straight lines are parallel.
(2) Two straight lines are cut by a third straight line. If the internal dislocation angles are equal, two straight lines are parallel. To put it simply: the internal dislocation angles are equal and the two straight lines are parallel.
(3) Two straight lines are cut by a third straight line. If they are complementary to each other, the two straight lines are parallel. To put it simply: the internal angles on the same side are complementary and the two straight lines are parallel.