If you can't multiply and calculate formulas, you will encounter the phenomenon that you can't do wrong questions in oral calculation and pen calculation, so you should do addition and subtraction well. This is also very important.
We should broaden our thinking and preview new knowledge. The development of mathematical thinking has two aspects, one is the ability of thinking logic, the other is the deformation of topics, and the third is the preview of new knowledge. Three aspects can make primary school students "see more" and "broaden their horizons".