I have data at 200 cells in column A starting from cell A11 ending at cell A210. At column B there are data at 30 cells starting from B11 ending at B40. The cells of column B have a connection with cells of row A. Cells B11:B30 should be every 10 cells in column A, this means B11 should be one of A11:A20, B12 should be one of A21:A30 etc The remaining 10 cells of column B (B:31:B30) should be every 20 cells in column A, so B31 should be one of A11:A30, B32 one of A31:50 etc. So I want to calculate at B1 how many cells doesn't follow the first rule and at B2 how many cells doesn't follow second rule. Any idea which formula to use?