I'm working on a little proggie in excel.

C16 = Some number

B19:B26 = some numbers

C19 =B19+B19/SUM($B$19:B$26)*C16
C20 =B20+B20/SUM($B$19:B$26)*C16
...
C26 =B26+B26/SUM($B$19:B$26)*C16

Lets say that if I only wanted to run the calculations on numbers >1000 ?
Eg if B19 was 1200, then the calculations for C19 wouldn't be carried out. How do I do that?

Thanks in advance