7. In the Cartesian coordinate system, the vertices of the square $O A B C$ have coordinates $O(0,0), A(100,0), B$ $(100,100), C(0,100)$. If a lattice point $P$ inside the square $O A B C$ (excluding the boundary and vertices) satisfies: $S_{\triangle P O A} \times S_{\triangle P B C}=S_{\triangle P A B} \times S_{\triangle P O C}$, then the lattice point $P$ is called a "good point". The number of good points inside the square $O A B C$ is $\qquad$.
7. 197 Detailed Explanation: Draw $P D, P E, P F, P G$ perpendicular to sides $O A, A B, B C, C O$ at points $D, E, F, G$ respectively. It is easy to see that $P F + P D = 100, P E + P G = 100$. From the problem, we can derive that $P D \times P F = P E \times P G, P D \times (100 - P D) = P G \times (100 - P G)$,
simplifying to $(P D - P G)(P D + P G - 100) = 0$, so $P D = P G$ or $P G = P F$.
Thus, point $P$ lies on diagonal $O B$ or diagonal $A C$;
Similarly, when $P$ is a point on diagonal $O B$ or diagonal $A C$, we have $S_{\triangle P O A} \times S_{\triangle P B C} = S_{\triangle P A B} \times S_{\triangle P O C}$.
Therefore, when $P$ is a lattice point on diagonal $O B$ or diagonal $A C$, point $P$ is a good point; hence there are a total of 197 good points.