China 999 Formula is the best textbook for children to connect. Will going to primary school be the same as abacus mental arithmetic and finger arithmetic, and will it be opposed and contradicted? Multiplication is the key content of primary school. Multiplication and multiplication formulas are a complete set of calculation tools, which have been recognized by more than 30 authoritative experts. The senior professor gave nine words: "It is a great contribution to mankind"! Easier to learn than multiplication. Children like it, parents are happy, and teachers are relaxed! The order of quick calculation is from high to low, and the current textbooks are from low to high. The addition and subtraction of China 999 Formula is also from low to high, which is consistent with the current textbook, impeccable, simple in steps, improving logical thinking ability, stimulating learning interest, enhancing self-confidence and having a sense of accomplishment. They are all top students in primary school. Primary school teachers find it amazing and eager to learn the "999 formula", so it is the best teaching material for children to connect.