How much social security does Taishan pay at its own expense a month?

Taishan paid social security at his own expense to 840 yuan for one month. According to relevant information, social security is paid at one's own expense, and the proportion of old-age insurance is 20%. According to the minimum base of Mount Tai, 4,200 yuan, 4,200× 20% a month = 840 yuan. Social security at one's own expense will not be interrupted. Individual contributions 15 years, when reaching the legal retirement age, can receive pension.