Answer by M. P. for Need help in excel formulas

Cell C1

= IFS(MOD(ROW(),5)=0, "", MOD(ROW(),5)=4, OFFSET(C1, -1, 0)/OFFSET(C1, -3, 0), TRUE, A1+B1)

You can calculate all your data using that formula simply. Just double-click or drag the fill handle of cell C1 down to copy the formula.