- lx: It is the number of surviving lives alive at exact age ๐ฅ.
- ๐๐ฅ: It is the number of deaths over the year of age ๐ฅ.
- qx: Probability of dying in year x
- px: Probability of surviving year x
1. l๐ฅ+1=๐๐ฅโ๐๐ฅ: It means the number of surviving person at age x+1 is equal to the number of surviving person at age x minus total deaths in year x
2. ๐๐ฅ=๐๐ฅ/๐๐ฅ: It means the number of deaths in a year divided by number of person living at age x
3. ๐๐ฅ=(๐๐ฅ+1)/lx: It means the probability of survivingย is equal to the number of people alive in year x +1 divided by the number of people died in the year x
4. px = 1-qx: It means that the probability of surviving is equal to 1 minus probability of death. In other words, the probability of surviving and probability of death equals 1
Collectively, ๐๐ฅ, ๐๐ฅ, ๐๐ฅ and ๐๐ฅ form what is called a โlife tableโ or โactuarial tableโ.ย ย