Mathematics in the fifth and sixth grades of primary school is still a bit difficult. For example, what number A is more than number B, how much number B is less than number A, the problem of cattle grazing, chickens and rabbits in a cage, meeting and chasing are all problems. To understand these problems, we must first master and be familiar with the knowledge points. For example:

1. It is known that the number of A is 25% more than that of B. How much is the number of B less than that of A?

The key to solve this kind of problem is to first understand the concept of fractional unit 1, and master what unit 1 is or how to distinguish units 1 in different situations under some special circumstances. At first glance, children who have not been exposed to this kind of problem may be confused, including many adults. Because we just used 1 from 3 to 2 and 1 from 2 to 3, isn't the result of the above question that the number of B is 25% less than that of A? The result is really not. Why?

Here can only use a practical example to illustrate what is going on. Suppose the number A is 5, and when the number B is 4, the number A is 25% more than the number B (or 1/4). How much is the number b less than the number a? It is easy to see that the number of B is less than that of A 1/5(20%) ... If we look closely, we find that the key to the above results is that when we ask how much 5 is greater than 4, the unit of the score is 1/4, and when we ask how much 4 is less than 5, the unit of the score is no longer 1/4. So it turns out that 5 is greater than 4, 1, 4 is less than 5, 1. If we extend the problem to the score, the result will be different. This result is mainly due to the difference in decimal units (that is, what is the unit of 1).

2, about cattle eating grass and other issues: the main knowledge points personally think that the society should let children understand the problems of constants and variables. Children have just come out of constant calculations, such as: how much is a catty of fruit, how much do you need to buy now, how much do you want to buy now or how much do you know, how much does it cost in total, how much does it cost to ask one, and so on. But for problems such as cattle eating grass, children should first know that the amount of grass is a variable, because grass is growing, and how much cattle eat today should increase the yield of grass today.

Of course, mathematics is a subject with strict logic. For children, the first thing to see is whether he has the talent to learn mathematics. To tell the truth, talent is still the main aspect to reach a certain level in learning mathematics. Secondly, we should master every knowledge point skillfully; The third is to expose children to different types of questions and master special solutions to some special questions. Do more exercise. Of course, it is better to have a better teacher to guide you.