Final answer:
To make a cell stay constant in an Excel formula, use absolute cell references by adding a dollar sign ($) before the column letter and row number of the cell reference.
Step-by-step explanation:
To make a cell stay constant in an Excel formula, you can use the dollar sign ($) before the column letter and row number of the cell reference you want to keep constant. This is called an absolute cell reference.
For example, if you want to make cell A1 constant, you would write $A$1 in your formula. If you only want to keep the column constant, you can use $A1 or if you only want to keep the row constant, you can use A$1.
By using absolute cell references, you can easily copy and paste formulas in Excel without the cell references changing.