first step
1, find the law, see the example for details. 1, 3,5, (parenthesis) 9, 1 1, 13.
Let's look at the numbers before and after the brackets, which are 5 and 9 respectively. We can find that they are all simple integers and they are all odd numbers. Then, after reading all the numbers in the topic, it is not difficult to find that the same rule of * * * is that the numbers are getting bigger and bigger, and they are all odd numbers, so there must be an odd number in brackets, and it is an odd number between 5 and 9, so there is only one answer, that is, 7.
3. Write 7 in brackets to complete the answer.
Second step
1, add, subtract, multiply and divide. See the example for details. 5- (parenthesis) = 1.
2. The brackets are 5 and 1 respectively, forming the equation 5-()= 1, so we only need to regard the brackets as unknowns and calculate the known numbers together, and we can get the unknowns.
3. After calculation, it is not difficult to find that the unknown number is 4 and get the answer.
Expand knowledge:
Entering the second grade of primary school, many parents suffer from not knowing how to help their children learn. The author thinks that we should focus on intuitive and concrete images according to the thinking characteristics of children in grade two of primary school, but we should pay attention to infiltrating mathematical thinking methods step by step to cultivate students' mathematical thinking ability.
First, the habit of carefully examining questions.
In the first grade, both teachers and parents have the habit of reading questions to their children. In the second grade, it is necessary to slowly cultivate children to learn to read questions and develop the habit of reading questions carefully.
Second, the habit of answering questions independently.
When answering questions, parents should not stare, guide or scold. When doing homework, the experience is not good, and the child is at a loss. They should pay attention to it, check it after finishing their homework, see if there are any problems, and cultivate the habit of children answering questions independently.
Third, correct habits in time.
For the wrong questions, this is the focus of your study. You will make mistakes, which means that your knowledge points have not been tested. This requires parents to cooperate with teachers to take care of their children. If you make mistakes, you should correct them in time and understand them.
Fourth, manage time habits.
Good academic performance is also related to learning efficiency. At the same time, children with high learning efficiency will learn more and get better grades, which requires parents to manage their children's time and pay attention to the combination of work and rest to improve their learning efficiency.