Hi everyone! I just need a little help. I was given this formula =IF(MID(A21,13,3)="DA1","yes",IF(MID(A21,13,3)="D01","yes","no")) and the question is this "The formula in cell C21 show be indicate yes if the data on cell A21 contains DA1. Correct the formula" the data in A21 is R2D2ETR2X2N9D01DA1ZQB631. Can anyone explain to me this formula? a big thanks!