Given the nature of what I think is your goal here (i.e. writing a mathematics puzzle for students), I would punctuate and employ repetition, so your students will see the pattern explictly.
Note that I am avoiding the explicit term "divide", so as not to explicitly instruct the students to perform mathematical division, and I am avoiding the more natural "remains", because of the connotation of "remainder" with "division".
To that end I would use "arrange" and "left over". Depending on your audience it may be suitable to relax the restriction of "remains".
Consider:
A restaurant has a fixed number of chairs.
- If they arrange them in tables of seven, no chair is left over.
- If they arrange them in tables of four, two chairs are left over.
- If they arrange them in tables of three, one chair remains.
The restaurant has less than 1000 chairs.
...(question discussed below)
Your final queston, "How many numbers smaller than 1000 are there for the number of chairs in the restaurant?" is tricky (although note I have change of to in for readability).
If the answer you are looking for is the number of solutions that meet the problem statements, then it is fine, albeit tricky, and some more-literal thinkers might feel cheated by such a question – perhaps that is the intent.
If, however, you want them to list the various possible numbers of chairs, you may need to be less ambiguous. If you are happy to be specific, I'd suggest an instructional footnote:
How many chairs are in the restaurant?
(There are X possible solutions; please list them all)
(You would substitute X for the right number of solutions.)