Why Chinese mathematics is so good, and it is still led by Indians in Silicon Valley, the problem lies in the multiplication formula.
Chinese people memorize 9 9 since childhood, while Indian children are familiar with 19 19, and because English is not a monosyllabic list number, the recipe is far less concise than Chinese, so Westerners generally do not memorize, most of the mental arithmetic is very poor.
For example, if you go to a gas station convenience store to shop, if you buy something for 16 yuan and take out 21, the East Asian and South Asian faces will immediately give 5 yuan in change, and if it is a white or black person, they will take 20, return 1 yuan, and then press the calculator to find 4 yuan.
For this reason, Britain once sent people to China to steal teachers, and they specially invited people to teach them before they learned it, which is the best learning in Western countries. From mental arithmetic, martial arts to Chaoshan songs, they are all a little bit furious.
American students generally accept that constructive mathematics is to add fifteen by one, and the same is true for pressing the calculator, which is also beneficial and useful for verification of unknown areas, but daily arithmetic is slow and logic is stronger than reaction.
Learning advanced math and statistics, the pursuit of quick calculations and concise answers will become obstacles, which is why American students who usually rely on iPad and Math app to do arithmetic, after entering calculus, it is the same as opening a hanging.
In short, if you want to prove the Riemann hypothesis and Fermat's theorem, it is a bit reluctant to memorize the formula.