By default Worldox does not index numbers as they are generally not probative. Dates of the month for example.
However, what if you need to search for the section or paragraph number of tax or other governmental regulations? If you try to search, for example, for IRM section 5.8.5.7, the search will fail.
There are two things that let you work around this problem. First, Worldox treats the periods as word separators (like the end of a sentence). If you replace the periods with spaces, e.g. “5 8 5 7" instead of “5.8.5.7." the search will work. However, it will be extremely slow, since it is doing a brute force search and not using the index.
If you can use a part of the designation that is indexed, it will be faster: “IRM 5 8 5 7". Also, the fewer numbers you use, the faster the search will be and may give you the same results. Chances are that “IRM 5 8 5" will give the same results as “IRM 5 8 5 7" and will be much faster.
A little experimentation with the various options should let you work around the issue.