Note: All Excel protection is relatively weak. It is useful to stop casual users but it is not for top secret information.
When you lock cells you need to be particularly careful about how much you lock. If the size of the numbers within a cell may change significantly, a locked spreadsheet may not allow the user to see the numbers as they will appear as ###### and the user won’t be able to resize the column or row.
To follow along go to 19.6
In order to allow a user to resize a column or row on a protected sheet (e.g. can’t see the numbers in H17 below), you will need to choose the Format Columns and/ or Format Rows option in the Protect Sheet dialogue box.
Note that this also allows the user to hide columns or rows so you need to decide what is important to you. Perhaps you should just make the column wide enough to handle any expected number.