Transliteration is more an art than a science, and opinions on the correct way to transliterate words vary widely. Each letter in the alefbet has a numerical value. Alef through Yod have the values 1 through 10. Yod through Qof have the values 10 through 100, counting by 10s. Qof through Tav have the values 100 through 400, counting by 100s.
Final letters have the same value as their non-final counterparts.
Because of this system of assigning numerical values to letters, every word has a numerical value. There is an entire discipline of Jewish mysticism known as Gematria that is devoted to finding hidden meanings in the numerical values of words. For example, the number 18 is very significant, because it is the numerical value of the word Chai, meaning life. Donations to Jewish charities are routinely made in denominations of 18 for that reason. It's an amusing notion, but Hebrew numbers just don't work that way.