1. **Problem statement:** We have a multi-level car park with 100 spaces. Let $D$ represent the set of spaces reserved for disabled persons. We want to write the set notation for the spaces that are *not* disabled spaces. 2. **Formula and explanation:** The set of spaces that are not disabled spaces is the complement of $D$ in the universal set $U$ of all parking spaces. Here, $U$ is the set of all 100 spaces. 3. **Set notation:** The complement of $D$ is written as: $$D^c = U \setminus D$$ This means all elements in $U$ that are not in $D$. 4. **Summary:** The set of spaces that are not disabled spaces is $D^c = U \setminus D$ where $U$ is the set of all 100 spaces.