1, law of addition:
Add two numbers with the same sign, take the same sign, and then add the absolute values.
Add two numbers with different signs, take the sign of the number with larger absolute value, and subtract the number with smaller absolute value from the number with larger absolute value.
Two opposite numbers add up to 0.
Add a number to 0 and you still get the number.
2, subtraction rule:
Subtracting a number is equal to adding the reciprocal of this number.
3, the multiplication rule:
Multiply two numbers, the same sign is positive, the different sign is negative, and then multiply by the absolute value.
Any number multiplied by 0 is 0.
Multiply several numbers that are not 0. When the number of negative factors is even, the product is positive. When the number of negative factors is odd, the product is negative.
4, division rules:
Dividing by a number that is not equal to 0 is equal to multiplying the reciprocal of this number.
Divide two numbers, the same sign is positive, the different sign is negative, and divide by the absolute value.
Divide 0 by any number that is not equal to 0 to get 0.
Formula:
Addition and subtraction, signed, absolute value, addition and subtraction cannot be run.
Multiplication and division, unsigned, conversely, whoever is in front is the first.
No matter addition, subtraction, multiplication and division, there is an absolute value, so be careful.
The sum of two opposite numbers is equal to 0.
When several numbers other than 0 are multiplied, only when the number of negative factors is even.
Dividing by a number that is not equal to 0 is equal to multiplying the reciprocal of this number.
The benefits of learning mathematics:
1, improve the ability to solve problems
Mathematics is a universal language, which can help us improve our ability to solve problems. Learning mathematics can cultivate our logical thinking and critical thinking, so as to better understand and solve various problems. From problems in daily life, such as calculating interest or estimating time, to problems in science, engineering and medicine, mathematics is a key tool to solve problems.
2. Enhance creativity and innovation.
Mathematics is a highly creative and innovative subject. Learning mathematics can stimulate our imagination and creativity and enable us to explore new concepts and ideas. Mathematics provides innovative tools and methods for various fields, from art and music to science, engineering and technology. By studying mathematics, we can master more tools and techniques and provide more opportunities for innovation and discovery.
3. Enhance communication and communication skills.
Mathematics is an accurate and objective language. Learning mathematics can help us improve our communication and communication skills, so as to better express our thoughts and opinions. Mathematics enables us to accurately express complex concepts and phenomena in the fields of science, engineering and technology. In addition, mathematics can help us better understand the knowledge system and structure of other disciplines.