Enea
If the numbers are measures, you can use the RANKING tool.
This is the 'winners platforms' in the toolbar (next to the alerters triangle).
Choose the dimension you wish to rank and the number of occurrencies you wish to see, and then tell the tool which measure to use for the comparisons.
For example, to find the highest paid employee, you will RANK the EMPNO based on the measure SALARY.
If the number is not a measure, create a new variable equal to the number field, and define this as a measure. You need not include it in the report layout, but you will be able to use it as the ranking variable.
Brian