If we've inadvertently missed a number when indexing, we used to be able to find the document by typing in "9xx..." in the search option and it would pull all the numbers that fall under (or above) it and, therefore, would be easier to locate. For example, I'm looking for the account number 2140463374 but obviously we've missed / transposed a number somewhere. So I would enter <2140463999 and have all the indexed numbers UNDER it pull up.