Multiplication formula table, also known as 99 multiplication formula table, is the basic formula for primary school students to learn mathematics, and it is also the most headache for every parent to help their children with their homework. Parents can tell their children that multiplication is one of the four operations, such as 2 times 6, that is, 2 increases 6 times, or 6 2 is added continuously.

"×" is a multiplication sign, the numbers before and after the multiplication sign are called factors, "=" is an equal sign, and the numbers after the equal sign are called products. 5 (factor) × (multiplication sign) 6 (factor) = (equal sign) 30 (product) factor is also called multiplier.

The formula for primary school students to learn "primary ninety-nine" is from "11" to "998 1", but in ancient times it was the other way around, from "998 1" to "224". Because the first two words of the formula are "99", people call it "Xiao 99" for short. It was only in the 13 and 14 centuries that this was reversed: "One gets one ... 998 1".

Jiujiu tables generally only use nine numbers from one to nine. Jiujiu table contains the commutativity of multiplication, so it only needs 8972, not "9872", 9 times 9 has the product of 8 1, and Jiujiu table only needs the product of 1+2+3+4+5+6+7+8+9 =45. In the Ming Dynasty, abacus also had 99 tables with 8 1 product. The 99 table of 45 items is called small 99, and the 99 table of 8 1 item is called big 99.

origin

China used the "99 formula" earlier. Sentences such as "3927", "684 18", "483 12" and "6636" can be found in books such as Xunzi, Guanzi, Huainanzi and Warring States Policy. It can be seen that "99 Multiplication Song" has already become popular.

Ancient Greece, ancient Egypt, ancient India, and ancient Rome did not have a carry system. In principle, they needed infinite multiplication tables, and it was impossible to have nine tables. For example, the Greek multiplication table must list 7x8, 70x8, 700 x8, 700x8, 700x8, 700x8, 700x8, 7000x8. In contrast, since the 99-99 table is based on the decimal system, 7x8=56, 70x8=560, 700x8=5600, 7000x8=56000, and only 7x8=56 is needed for one representation.