Suppose you have a string "abc123def43cd" and you want to count numbers in this.
If your string is in A1, use following formula –
=SUMPRODUCT(LEN(A1)-LEN(SUBSTITUTE(A1,ROW(1:10)-1,"")))
OR
=SUMPRODUCT(–ISNUMBER((–MID(A1,ROW(INDIRECT("1:"&LEN(A1))),1))))
Assuming your text is less than 1000 characters long, you could use this formula as well…
=SUMPRODUCT(–ISNUMBER(-MID(A1,ROW($1:$999),1)))
Awesome!!!