First of all, cultivate interest and let him feel the charm of mathematics. Master Chen Shengshen said that "mathematics is interesting", which made him understand this point.

Then show him some math-related books to develop his intelligence, or play some math games, and teach him some skills and principles according to the content of school education, so that he can use these skills and principles when playing.

If your child's interest develops rapidly, you can tell him some difficult mathematical principles. Children are easy to accept new things when they are 5 years old. As long as he is interested, it may be enough for others to attend primary school for six years.

However, it is forbidden to encourage children to learn as much as they want. Let nature take its course, children have other talents to develop.