join 2 Blankcells formulas together

is it possible [although I don't seem to be able to do it] to join 2 Blankcells formulas

i.e.

=COUNTBLANK('Fees( HK)'!I8:I16) gives me the correct answer 2

=COUNTBLANK('Fees( HK)'!I24:I25) gives me the correct answer 2

so I want to join these into one formula to get the answer 4

i.e.

=COUNTBLANK('Fees( HK)'!I8:I16) plus =COUNTBLANK('Fees( HK)'!I8:I16)

thanks