When you protect a worksheet in excel but unprotect certain cells, why can't you change the format of the cells or insert comments?

because you have protected the worksheet. You may have unprotected the cells but the worksheet is prevented from changing the format. You can change the cell values but not the format. That's the way it works!

. I have 2 sets of data (x and y), I want to count the data less and more than a given data (for x or y) that below that value and also (less and more than) the given data above that value. What is the proper function I can use. Many thanks

Countif is the function