The letters of the Hebrew alphabet are also numbers, depending, not on columnar position as in the decimal system, but on the position in the alphabet.
Thus, the first 9 letters from Aleph to Teth represent the first 9 numbers.
There is no letter valued at zero.
God does not regard any of His creations as having zero value.
The next 9 letters from Yod to Tsadde represent the numbers 10, 20 ... 90.
The remaining 4 letters from Qof to Tav represent the numbers 100, 200, 300 and 400.
Century numbers above 400 are denoted by combinations of the last four letters.
Thus 500 = Tav Qof (400 + 100).
600 = Tav Resh (400 + 200).
700 = Tav Shin (400 + 300).
800 = Tav Tav (400 + 400).
The last century number requires three letters.
900 = Tav Tav Qof (400 + 400 + 100).
Thousands are represented by the letters positioned at the extreme right.
For example in numbering years on the Jewish calendar, we are now in the 5000s. This is represented by Hey at the rightmost position.
For the value of studying Hebrew, see Hebrew Language.