i do have a problem with my formula. =(IF(OR(D4<>0,E4<>0),SUM(D$4:D4)-SUM(E$4:E4),0) i tried it billion times. but i can't click the E4 cell at my worksheet. why? can someone told me whats wrong? i do tried another formula. =(IF(OR(D4<>0;E4<>0);SUM(D$4:D4)-SUM(E$4:E4);0). it worked. at the beginning. when i tried to drag it, it doesnt change at all. the number is still same. can anyone tell me? i really need you advice. thank u