What is required to use a custom number filter in Excel?

To effectively use a custom number filter in Excel, it is essential to activate the filter feature. Activating the filter allows you to access the filtering options, including custom filters that let you define specific criteria for displaying data. Once the filter is enabled on your data set, you can apply custom number filters to refine the displayed information based on your specified rules.

Other options do not represent prerequisites for employing a custom number filter. For instance, data does not need to be sorted for a custom number filter to function. Additionally, cell ranges do not have to be formatted specifically to use this feature, as filtering can be applied regardless of cell formatting. Lastly, it is not necessary for all cells to contain data; you can still filter based on the existing data, even if some cells are empty. Thus, the key requirement is the activation of the filter.