1, addition of the same sign, subtraction of different signs: When two rational numbers have the same sign, they can add their absolute values and keep the same sign. For example, for two positive rational numbers 3 and 5, their sum is 8; For two negative rational numbers -2 and -4, their sum is -6. When the signs of two rational numbers are different, their absolute values can be subtracted and the sign of the number with the larger absolute value can be kept. For example, for positive rational number 6 and negative rational number -3, their sum is 3.
2. The commutative law of addition: the addition of rational numbers satisfies the commutative law, that is, the sum of two rational numbers is the same regardless of their order. For example, rational numbers 2 and 3, the result of 2+3 is 5, and the result of 3+2 is also 5.
3. Association Law of Addition: The addition of rational numbers satisfies the association law, that is, regardless of the order of rational numbers, their sums are the same. For example, the result of rational number 1, 2, 3, (1+2)+3 is 6, and the result of 1+(2+3) is also 6.
The law of rational number addition is the law of rational number addition in mathematics. Rational number refers to a number that can be expressed as the ratio of two integers, including positive integer, negative integer and zero. Through these addition rules, the addition operation of rational numbers can be simplified and made more convenient and faster. These laws are also in line with people's experience in daily life, and it is easier for people to understand and apply.
Practical application of rational number addition rule
1, Financial Management: In our daily life, we need to conduct various financial management, such as deposit, repayment and interest calculation. These involve the quantity and flow direction of money. The quantity of money can be expressed as a rational number, and it is easy to calculate the total amount and residual amount through the addition rule of rational numbers.
2. Temperature calculation: Temperature is a commonly used quantity in physics and can be expressed in degrees Celsius or degrees Fahrenheit. When the temperature needs to be added or subtracted, we can convert Celsius or Fahrenheit into a rational number, and then calculate it according to the rule of rational number addition, and then convert the result back to the unit of temperature.
3. Flight calculation: In aircraft navigation, route calculation and altitude calculation are needed. These calculations involve the addition and subtraction of voyage and altitude equivalence, and these values can be expressed as rational numbers.