I have a large work sheet with existing data. How can I add a formula to all the data (cells with data) at one time. Entering the formula one cell at a time is not possible e.g there are 10 cells with data and I want to add a same formula say multiply all 10 cells by $A$100, so that every time I change A100 cell value, all the corresponding cell value changes

Help is highly appreciated

Thanks and regards

Shora