Below is a possible solution to the challenge –Challenge 4 – SUM of Multiplication of Preceding Digits by Succeeding Digits
Given your numerical string is in A1, use following formula –
=IFERROR(SUMPRODUCT((MID(A1,ROW(INDIRECT("1:"&LEN(A1)-1)),1)*MID(A1,ROW(INDIRECT("2:"&LEN(A1))),1))),0)
The answer would be as follows
