The CSV file should have the following columns (in order):
1. Question text (e.g., "Solve for x: 2x+5=15")
2. Solution text (e.g., "x = 5")
3. Difficulty level (e.g., "easy", "medium", "hard")
4. Section (optional, e.g., "Algebra" or "Calculus")
Example (without a header row):
"Solve for x: 2x+5=15","x = 5","easy","Algebra"
"Find the derivative of x^2","2x","medium","Calculus"