Elementary school knowledge for half a year, because at the beginning, junior high school knowledge for half a year, because almost have the concept of mathematics, high school one year, high number is very simple, half a year, one * * * two and a half years, which is relative to adults, children's brains have not developed, if they accept mathematics, they will be very boring, and it will be difficult to learn if they conflict with each other. If an adult really studies hard, it only takes three years at most from the first grade mathematics knowledge to the advanced mathematics.