1. The problem is to understand the sets $A = \{1, 3, 5\}$ and $B = \{6, 7\}$.\n\n2. Sets are collections of distinct elements. Here, $A$ contains three elements: 1, 3, and 5. Set $B$ contains two elements: 6 and 7.\n\n3. We can perform operations such as union, intersection, and difference on these sets. For example, the union $A \cup B$ includes all elements from both sets without repetition.\n\n4. The union is $A \cup B = \{1, 3, 5, 6, 7\}$.\n\n5. The intersection $A \cap B$ includes elements common to both sets. Since $A$ and $B$ have no common elements, $A \cap B = \emptyset$.\n\n6. The difference $A - B$ includes elements in $A$ not in $B$, so $A - B = \{1, 3, 5\}$. Similarly, $B - A = \{6, 7\}$.