China's basic education has always been very strong, and it is basically a link. If you want to teach yourself mathematics (if you don't have a foundation in mathematics), you must move forward step by step from the first grade mathematics textbook.

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From basic addition and subtraction, to multiplication and division, and then to gradual upgrading, we must lay a good foundation at every step, otherwise it will be much more difficult to learn in the future. In addition, there must be mathematical thinking, such as from general to special, from special to general, functional thinking, mapping thinking and so on. Learn association and cultivate sensitivity to numbers.

At present, self-learners who have no foundation only focus on practicing the foundation of mathematics. Do every basic training problem well in the textbook and remember all the basic mathematical formulas. In addition, there are a large number of thinking expansion questions in primary school mathematics for students' thinking training. It is often necessary to find other ways to do it, so it is normal that some primary school math problems cannot be done. Another possibility is that the mind has solidified. When you see a problem, you will subconsciously do it in your usual way. Sometimes a little flexibility is needed, and the answer comes naturally.