The multiplication formula is the basic calculation rule of multiplication, division and square root in ancient China. It has been used for more than two thousand years, and Jiujiubiao is also the basic skill of elementary school arithmetic.

The ancient multiplication formula is from top to bottom, from "998 1" to "one to one", which is contrary to the order of use. Therefore, the ancients used the word "99" at the beginning of the multiplication formula as the name of this formula, also known as "99 table", "99 song" and "99 multiplication table". From "one to one" to "10000× 10000", it was the other way around in ancient times, from "998 1" to "one to one". Because the first two words of the formula are "99", people call it "99" for short.

It was not until 13 and 14 centuries that it became our 99 formula "one by one19981".