To remove numeric characters from a text string, you can try this experimental formula based on the TEXTJOIN function, new in Excel 2016. In the example shown, the formula in C5 is:
=TEXTJOIN("",TRUE,IF(...

To use data validation to allow a list of specific characters only, you can use a rather complicated array formula based on the COUNT, MATCH, and LEN functions. In the example shown, data validation is applied with this...

To sum the top values in a range, you can use a formula based on the LARGE function, wrapped inside the SUMPRODUCT function. In the generic form of the formula (above), rng represents a range of cells that contain...

To create a formula with a dynamic sheet name you can use the INDIRECT function.
In the example shown, the formula in C6 is:
=INDIRECT(B6&"!A1")
Note: The point of this approach is it lets you to build...

To build a dynamic worksheet reference - a reference to another workbook that is created with a formula based on variables that may change - you can use a formula based on the INDIRECT function.
In the example shown,...

To get cell content with a given row and column number, you can use the ADDRESS function together with INDIRECT. In the example shown, the formula in G6 is:
=INDIRECT(ADDRESS(G4,G5))
How this formula works
The Excel...

To reference a named range on another sheet, you can use the INDIRECT function with the required sheet syntax. In the example shown, the formula in D6 is:
=SUM(INDIRECT("'"&B6&"'!"&C6...

To conditionally sum identical ranges that exist in separate worksheets, all in one formula, you can do so with the SUMIF function + INDIRECT, wrapped in SUMPRODUCT. In the example, the formula looks like this:
=...

To convert a string to an array that contains one item for each letter, you can use an array formula based on the MID, ROW, LEN and INDIRECT functions. This can sometimes be useful inside other formulas that manipulate...

If you need to sum or add the bottom values in a range, you can do so with a formula that uses the SMALL function wrapped inside the SUMPRODUCT function. In the generic form of the formula (above), rng represents a...

To use count a non-contiguous range with criteria, you can use the COUNTIF function together with INDIRECT and SUM. In the example shown, cell I5 contains this formula:
=SUM(COUNTIF(INDIRECT({"B5:B8","...

To search multiple worksheets in a workbook for a value and return a count, you can use a formula based on the COUNTIF and INDIRECT functions. With some setup, you use this approach to search an entire workbook for a...

To test if a worksheet name exists in a workbook, you can use a formula based on the ISREF and INDIRECT functions. In the example shown, the formula in C5 is:
=ISREF(INDIRECT(B5&"!A1"))
How this formula...

You can reverse a text string with the TEXTJOIN and MID functions, by using an array constant. In the example shown, the formula in C5 is:
=TEXTJOIN("",1,MID(B5,{10,9,8,7,6,5,4,3,2,1},1))
How this formula...

To convert a column letter to an regular number (e.g. 1, 10, 26, etc.) you can use a formula based on the INDIRECT and COLUMN functions.
In the example shown, the formula in C5 is:
=COLUMN(INDIRECT(B5&"1...