If you Can't type numbers or formulas or enter data into Excel cells then it might be a problematic Add-in causing the problem. Here are some working fixes that may help.

Microsoft Excel can’t insert new cells because it would push non-empty cells off the end of the worksheet. These cells might appear empty but have blank values, some formatting, or a formula.

Can't See Columns in Excel. Over the course of a long night, you prepared your spreadsheet. However, when you looked at it the next morning, you find that you cannot see several columns.

As you can see in the screenshot below, the formula works without these spaces. You can access an Excel workbook and accompanying video below for combining a formula and text in the same cell.