One and one make one

One and two make two, two and two make four

One and three make three, two and three make six, three and three make nine

One five gets five two five one thirteen fifty five four five twenty five five twenty five

One six gets six two six two three six eight four six twenty four five six thirty six six thirty six

One seven gets seven two seven four three seven twenty one four Seven twenty eight five seven thirty five six seven forty two seven seven forty nine

One eight is eight two eighty six three eight twenty four four eight thirty two five eight forty six eight Forty-eight, seven, eight, fifty-six, eight, eight, sixty-four

One nine is nine, two, nine, eight, three, nine, twenty-seven, four, nine, thirty-six, five, nine, forty-five, six, nine, fifty-four, seven-nine Sixty-three, eight, nine, seventy-two, nine, nine, eighty-one

Extended information

Characteristics

1. The nine-nine table generally only uses one to nine. 9 numbers.

2. The nine-nine table includes the commutability of multiplication, so only eight nine seventy-two is needed, and "nine eight seventy-two" is not needed. 9 times 9 has 81 sets of products, and the nine-nine table only needs It requires 1+2+3+4+5+6+7+8+9 = 45 terms. The abacus in the Ming Dynasty also used the nine-nine table with 81 sets of products. The nine-nine table with 45 items is called the small nine-nine, and the nine-nine table with 81 items is called the big nine-nine.

3. The shortest multiplication table in the ancient world. The Mayan multiplication table requires 190 items, the Babylonian multiplication table requires 1770 items, and the multiplication tables of Egypt, Greece, Rome, India and other countries require infinite items; the 99 table only needs 45/81 items.

4. There is a rhythm when reading aloud, making it easier to memorize the entire table.

Development of formulas

China used the "Nine-nine formulas" earlier. In "Xunzi", "Guanzi", "Huainanzi", "Warring States Policy" and other books, you can find "three-nine-twenty-seven", "six-eight-forty-eight", "four-eight-thirty-two", "six Six thirty-six" and other sentences. It can be seen that as early as the Spring and Autumn Period and the Warring States Period, the "Nine-Nine Multiplication Songs" had already become popular.

Jiujiu table, also known as Jiujiu song and Jiuyin song, is the basic calculation rule for multiplication, division, square root and other calculations in ancient Chinese calculations. It has been used to this day by more than 2,000 people. Year. Junior elementary school students and some school-age children can recite it. However, this simple multiplication table was not known in Europe until the beginning of the thirteenth century.