99 multiplication table is a simple multiplication calculation method invented by China in ancient times, and the product can be obtained quickly by formula.

From "one to one" to "998 1", it covers the product of nine nines and related formulas. For example, "22 is like four", "three three get nine" and "four forty-six".

These formulas are arranged in numerical order, which is convenient for memory and use. It is not only widely spread in China, but also has an impact on global mathematics education.