What is the formula and date of winter?

1929 did not shoot; Walking on the ice in 3949; 59 and 69, watching willows along the river; 79 River freezes, 89 Yan returns; 99 plus 19, plowing cattle everywhere.

1, 1929 Don't make a move: 1929 After the solstice in winter, the weather is cold, and putting your hands outside will be unbearable and even cause frostbite, so you can't help but put them in your pocket, which means "Don't make a move".

2.3949: 3949 Walking on the ice is the coldest season of the year. There is thick solid ice in the river, so pedestrians can walk safely on the river.

3. Looking at willows along the river in May, 1969: At the coldest time, the weather began to get hotter in May, 1969. Rivers planted with willow branches began to sprout, and everything gradually recovered to eliminate the winter depression. People could not help but see willows.

When the snow and ice begin to melt, the frozen river will slowly thaw and the sound of water will be heard. In the warm weather in August and September, swallows will fly back from the south to nest and start a new round of busy and endless cycle.

5.99 plus 19, plowing cattle everywhere: 99 is the alarm in the 24 solar terms. The weather is getting warmer, and there is spring water gradually. The weather has been warmer. Most parts of China have entered the spring ploughing season, and cattle work is everywhere, which indicates new hope and a new beginning.

Characteristics of Jiujiu Watch

General 1 and 99 tables only use 9 numbers from 1 to 9.

2. Jiujiu table contains the commutativity of multiplication, so only 8972 is needed, and "9872" is not needed. 9 times 9 has a product of 8 1, and 99 tables only need it.

Regular products. 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.

3. The shortest multiplication table in the ancient world. Maya multiplication table must have 190, Babylon multiplication table must have 1770, and Egypt, Greece, Rome, India and other countries must have infinite multiplication tables; Only 45/8 1 item is needed for the 999 table.

4. There is rhythm when reading aloud, which is convenient for memorizing the whole table.

5. Jiujiu watches have existed for at least 3000 years. It was used for calculation from the Spring and Autumn Period and the Warring States Period, and was improved and used for abacus in the Ming Dynasty. The 99 standard is also the basic skill of elementary school arithmetic.