This has me totally stumped......

Is it possible to combine column A with column B to get this result?

Column A Column B Column C
8888021100013 00020 888802110001300020
9310004342206 00003 931000434220600003

I can combine the A&B ok but I keep losing the zeros in column B and my
result looks like this:

Column A Column B Column C
8888021100013 00020 888802110001320
9310004342206 00003 93100043422063

The string in column B must be 5 numbers and I have tried many
differing formatting options but just cant seem to get the wanted
result.

Would really appreciate if someone could point me in the right
direction.

Regards,
Dean