1, rational number addition law and algebraic addition and subtraction law: In mathematics, rational numbers include integers and fractions. When adding different symbols, you need to put positive and negative numbers on opposite sides of the symbol and then calculate the sum of their absolute values. Algebra's law of addition and subtraction: In algebra, when different symbols are added, two numbers need to be added, and then the number with opposite signs is taken as the result.
2. The operational nature of addition with different signs: when adding with different signs, if the signs of two numbers are the same, their sum is positive; If the signs of two numbers are opposite, their sum is negative.
3. Pay attention to the following points when adding different symbols: First, if the signs of two numbers are opposite, then their absolute values are equal; Secondly, when adding different symbols, we should pay attention to the transformation of symbols; Finally, we need to pay attention to the change of calculation order and symbol.
Mathematics related knowledge
1, algebra: algebra is a branch of mathematics, which mainly studies the properties and operation rules of algebraic elements such as numbers, letters and symbols. The basic concepts of algebra include algebraic operations, algebraic expressions, equations, variables, functions and so on. Through algebra, we can use symbols and formulas to express various quantitative relations and mathematical laws.
2. Geometry: Geometry is a branch of mathematics, which mainly studies the properties and relationships of geometrical features such as shape, size and position. The basic concepts of geometry are points, lines, surfaces, angles, triangles, quadrilaterals, circles and so on. Through geometry, we can better understand the shape, structure and motion law of objects.
3. Probability theory: Probability theory is a branch of mathematics, which mainly studies the statistical laws of concepts such as random events, random variables and probability distribution. The basic concepts of probability theory include sample space, events, independence, probability distribution and so on. Through probability theory, we can better understand the statistical laws of random phenomena, and use probability methods to predict and analyze them in real life.