For mathematical formulas, the most important thing is to be familiar with the chest, keep practicing, brush the questions, and explore the ideas of learning and solving problems.

If you want to buy such a mathematical formula manual, it is better to prepare a notebook for your child, let him copy the formulas in the book himself, and match them with relevant typical examples, so that it is more meaningful and effective to read and consolidate from time to time.

Because children can copy and recite formulas at the same time.

Then, by constantly brushing questions, learning and understanding the formula may have more problems and changes when solving problems, and expand your own ideas and methods of solving problems.

If learning should be a discipline that pays attention to methods, mathematics is definitely one of them. You don't have to remember these formulas to know how to use them. Sometimes, if you don't have the relevant problem-solving skills, you just can't solve it, even though you know the relevant formula. But if you have done a similar topic, even if it seems difficult, you may give an answer orally.

Therefore, personally, I think that only by buying a handbook on the laws of mathematical formulas in primary schools can it be convenient for children to find the relevant formulas, unlike the fact that the text is divided into chapters, and it is necessary to turn to the corresponding chapters to find the formulas. But with this manual, it is easier for children to look through formulas if they want to use it, but they just can't remember it, that's all. It is not obvious that it is more useful.

Then you can buy a copy book and copy the formula mentioned in the next lesson, which can also have the same effect.

Generally speaking, I think it is of little significance to children's learning. Children basically throw them away, and they don't remember where they put them in the back, let alone use them. For the study of mathematics, my suggestion is to buy test papers of various types, that is, to constantly brush the questions and constantly refresh the children's problem-solving skills. That's all that matters. And by brushing questions, I also practice and use related formulas to help me remember them. Practice and formula memory complement each other and are indispensable.