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 99-99 multiplication melody is also often called "Xiao 1999". The formula of "occupation" that students learn is

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. Only in 13 and 14 centuries did it become our formula "one by one" ... 998 1 ".

Jiujiubiao, also known as Jiujiuge and Jiuyinge, is the basic calculation rule in multiplication, division, square root and other operations in ancient China. It has been used for more than two thousand years. Pupils and some school-age children can recite it. But Europe didn't know this simple multiplication table until the beginning of 13 century.