So you want a counter that counts to 100 and then begins at 0 (or 1) again?

If I'm understanding correctly I would do the following:

[bang(
|
[float]X[+ 1]
|
[select 100]
|
[0(


the 0 message at the end could also be a 1 depending on if you want the counter to begin on 0 or 1, it is sent to the right inlet of float.

the outlet of float is, in addition to [select], also sent wherever you want the counter to be output to.

here is the same patch as a subpatch (keeping in mind that the 0 message still must be connected to the right inlet of float):

[inlet]
|
[b]
|
[float]X[+ 1]
| \
| [outlet]
|
[select 100]
|
[0(

...of course you can always use the [counter] object.  [counter 100] will probably do the trick all by itself.
and finally, if i'm understanding incorrectly and you wanted it to count up and back down, use the example that was posted previously with the absolute values and [wrap],
or use [counter 100] with the up/down message sent to it, you'll have to check the help file for exactly what that message is...

hope something in there helps.

-Ben