If you wish to know the number of entries in a table you have done, the best is to use the function Count or Counta. These two functions will provide you with the number of cells that are occupied in an area.
If you wish to know only the numbers of numbers then use the count function.
If you wish to know the number of non empty cells in an area (meaning counting the total number of entries (numbers, characters, ...) then use the counta funtion.
See the example here over and see how the count and counta differs.