=SUMPRODUCT(--MID(Zimoveiskaya;ROW(INDIRECT("1:"&LEN(Zimoveiskaya)));1))
Zimoveiskaya
is a cell in which the text is presented in a sequence of numbers=IFERROR(
MOD(SUMPRODUCT(--MID(Zimoveiskaya;ROW(INDIRECT("1:"&LEN(Zimoveiskaya)));1));9)
+(MOD(SUMPRODUCT(--MID(Zimoveiskaya;ROW(INDIRECT("1:"&LEN(Zimoveiskaya)));1));9)=0)*9;
-1
)
SUMPRODUCT
lists and adds up all the numbers.Find more questions by tags Google Sheets