Calculating a custom total for a column on iPad mini and Numbers
Summing a column with conditions can be done with the SUMIF() or SUMIFS functions.


  The SUMIF function is a worksheet function that adds all numbers in a range of cells based on one criteria (for example, is equal to 2000). To add numbers in a range based on multiple criteria, try the SUMIFS function.


For example:

=SUMIFS(A2:A10, A2:A10, “&gt;0”)

Looks at all values greater than 0 and totals them up.





To use formulas and functions in Numbers for iOS:


Select the cell in which you wish to have the calculation.  (In the attached example, for instance, cell A11)
Type the equals sign character = or select circled equals sign icon.
Start typing the name of the function you wish to use, or tap the fx at the top left of the virtual keyboard to see a list of functions to choose from.


For more detailed information on how to use formulas and functions in Numbers for iOS, please see the official documentation here from Apple.