The poor math foundation in Grade One needs to be made up by preview, basic practice, cumulative error correction and breakthrough. We should read the textbook carefully, understand the learning content in the recent stage, pay attention to the formation process of knowledge, start learning from the most basic mathematical knowledge, be familiar with the definitions of various formulas, understand the steps of solving different types of problems, and skillfully do the simplest problems first. At the same time, we should check our mistakes in time, carefully analyze the reasons and solve them one by one.