Format letters and numbers as subscripts in Microsoft Word 2013 when you need to write mathematical equations or chemical formulas and don't have the Mathematics or Chemistry add-in installed. Subscript letters and numbers appear slightly lower than the rest of the text, while superscript letters and numbers appear slightly higher than the text. You can make subscript or superscript letters or numbers by using the buttons in the Font group or by using keyboard shortcuts.
Make Subscript or Superscript Letters
Type the formula into the Word document and then select the letters or numbers you want to position slightly lower than the text on the line. To select several letters, hold "Ctrl" and select each one. Click the "Subscript" button in the Font group on the Home tab to make the letters subscript. Press the "Superscript" button to make them superscript. Alternatively, use the "Ctrl-=" or "Ctrl-Shift-=" keyboard shortcuts for subscript or superscript respectively. To undo the changes, press the keyboard shortcuts again or press "Ctrl-Z." Save the document by pressing "Ctrl-S."