To sum digits in a value in Excel, you can use the **SUM** function. This function takes two arguments: the first is the range of cells to sum, and the second is the number of digits to sum. For example, to sum the digits in the value 1234, you would use the following formula:

`=SUM(A1:A4,4)`

This would return 10, since 1+2+3+4 = 10.

You can also use the **SUM** function to sum a range of cells that contain values with different numbers of digits. For example, if you have the values 12, 345, and 678 in cells A1 through A3, you could use the following formula to sum all of the digits:

`=SUM(A1:A3,LEN(A1:A3))`

This would return 36, since 1+2+3+4+5+6+7+8 = 36.