First, the addition formula:
1, positive number plus positive number: a+b = a+b.
2. plus minus: a+(-b) = a-b.
3. negative plus positive: (-a)+b = b-a.
4. Negative number plus negative number: (-a)+(-b)=-(a+b)
Second, the subtraction formula:
1, positive number MINUS positive number: a-b, which can be regarded as a MINUS B.
2. Positive number of burden reduction: a-(-b), which can be regarded as adding B to A. ..
3. Negative negative positive: (-a)-b, which can be regarded as negative B on the basis of -a. ..
4. Negative burden reduction: (-a)-(-b), which can be considered as adding B on the basis of -a.
Rational number refers to a number that can be expressed as the proportional form of two integers, including positive integer, negative integer, zero, and finite decimal and infinite cyclic decimal that can be reduced to decimal form.
Rational numbers include integers (i.e. denominator is 1), true fractions (numerator is less than denominator), fractional fractions (numerator is greater than or equal to denominator) and cyclic decimals (infinite acyclic decimals can be simplified to cyclic decimals).
Methods of learning addition and subtraction formulas of rational numbers well
1. Understanding the concept of rational numbers: First, we must clarify the definition and characteristics of rational numbers and understand that rational numbers can be expressed in the form of the ratio of two integers.
2. Master the addition formula: remember the formula of rational number addition, including positive plus positive, positive plus negative, negative plus positive, negative plus negative. At the same time, do more exercises to deepen the understanding and application of formulas. Understand the relationship between subtraction and addition: subtraction can be regarded as the inverse operation of addition. When using the addition formula, subtraction needs to be converted into addition, for example, subtraction needs to be converted into the form of addition of opposites.
3. Do more exercises and practical problems: through constant practice and solving practical problems, consolidate and apply the learned addition and subtraction formulas. You can start with simple questions, gradually increase the difficulty and improve your problem-solving ability. Summary: Summarize some special situations or complex problems encountered, and form your own way of thinking and methods to solve problems.