Every formula and function must begin with an equal sign. This tells Excel that the cell contains a calculation rather than just plain text.
Instead of typing numbers directly (e.g., =10+5 ), it is best practice to use cell references (e.g., =A1+B1 ). This ensures the result updates automatically if the values in those cells change. Essential Functions for Every User Overview of formulas in Excel - Microsoft Support Microsoft Excel Functions and Formulas
are custom equations you create yourself to perform calculations, such as =A1+B1 . Every formula and function must begin with an equal sign