Senior two has to solve a math problem, which is about vertical calculation.
We need to find a suitable number, so that the result of multiplying this number by 4 meets some conditions in vertical calculation.
Suppose the number we are looking for is a, and the number multiplied by 4 is B.
According to the topic, we know that the number obtained by multiplying 1 and A by 4 is B. Therefore, A× 4 = B.2. B is a two-digit number. Its ten digits are 2 and its one digit is 8. So, b = 28.
Now we need to solve this equation and find the value of a.
The calculation result is: a = 7.
So, the appropriate number is: 7.
mathematical knowledge
1. Arithmetic: including additive commutative law, additive associative law, multiplicative commutative law, multiplicative associative law, multiplicative distributive law and division.
2. Function and derivative: mainly examine set operation, related concepts of function, definition range, value range, analytical formula, limit, continuity and derivative of function, etc.
3. Plane vector and trigonometric function, trigonometric transformation and its application: this is the focus of the college entrance examination, but it is not difficult. It mainly produces some basic or intermediate problems.
4. Sequence and its application: This is the key and difficult point of the college entrance examination, which mainly produces some comprehensive questions.
5. Inequality: The solution and proof of inequality are mainly investigated, and it is rarely investigated separately, mainly by comparing the sizes in the solutions.
6. Probability statistics: This part is related to our life and is an applied problem.
7. Qualitative and quantitative analysis of spatial position relationship: mainly to prove parallelism or verticality, and to find angle and distance.
8. Analytic geometry: This is the difficulty of the college entrance examination, which requires a large amount of calculation and generally includes parameters.
Methods of learning mathematics
1. Make and follow the study plan: make a detailed study plan according to the individual's study goals and timetable, so as to study regularly and step by step.
2. Understand the basics: In the process of learning, we must understand the basic concepts and formulas of mathematics instead of rote learning. For the knowledge points you don't understand, you should actively seek help or study and discuss with your classmates.
3. Practice problem-solving skills: Exercise problem-solving skills and calculation skills by doing problems. Problem-solving skills and calculation skills are the basis of learning mathematics, and they can only be mastered skillfully through a lot of practice.
4. Develop learning strategies: When learning mathematics, you should know how to apply what you have learned to practical problems and how to solve mathematical problems. Therefore, in order to better understand and master mathematics knowledge, it is necessary to formulate corresponding learning strategies.
5. Find good learning resources: When learning mathematics, you can use good learning resources such as textbooks, online courses, math games, etc. to learn math knowledge more vividly.
6. Communicate with people: In the process of learning mathematics, you can communicate with people. Communicating with others can help us understand the problem and solve it with the help of others' experience.