In B1:

="747" & RIGHT(A1,LEN(A1)-8)

Or if they are 12 digits then

="747" & RIGHT(A1,4))

HTH

"Xavie" wrote:

I have some 10,000 number with various digit like 199601013800, 200505010002.
The first 8 digit must be replaced to 747. What formula must be used ?