I am unable to figure out how to get the formula below to work properly. It
is for figuring out the amount of product sold for the year where B3=cost of
item,C3=starting inventory on Jan 1st, D3=inventory purchased between Jan.
1st and 3/31, E3=inventory on 3/31, F3=inventory purchased between Apr. 1st
and 6/30, G3=inventory on 6/30, H3=inventory purchased between Jul. 1st and
9/30, I3=inventory on 9/30, J3=inventory purchased between Oct. 1st and
12/30, and K3=ending inventory on 12/31. The formula help for excel is very
poor and confusing. It will not actually tell me what the specific problem
is, nor how to fix it.

=SUM(B3*(C3+D3(-(IF(AND(E3=0,G3<0),E3,0))),(IF(AND(G3=0,I3<0),(+ F3-G3),0)),(IF(AND(I3=0,K<0),(+F3+H3-I3),0)),(IF(K3=0),(+F3+H3+J3-K3),0)))