China Naming Network - Almanac query - What is the formula for counting nine in cold weather?

What is the formula for counting nine in cold weather?

Formula:

1929 didn't shoot, walked on the ice in 3949, watched the willows by the river in 5969, opened the river in 79, added 19 in 99 for 89 years, and plowed cattle everywhere.

Origin:

"99" is the product of farming society, with a long history, which has been passed down from mouth to mouth among the people. It is the experience summed up by the ancients on the basis of generations of production and life practice, using some ecological reflections and weather signs in nature.

It is quite scientific and still plays a guiding role in the arrangement of people's production and life, so it has always been very popular, widely circulated in people's mouths and reflected in people's behavior.