Open your Word document. Go to Insert tab. On the Table Tools Layout tab in the Data group click Formula.
Choose Insert Equation and select Insert New Equation from the bottom of the built in equation gallery.
If you set up Word to check the spelling and grammar of text in other languages and a document contains text in multiple languages Word displays readability statistics for text in the last language that was checked. You can type in the Formula box select a number. Click the icon to insert an. If the cell is not empty delete its contents.