Introduction:
Solving questions that involve theoretical calculations or derivations from previous years' papers requires a systematic approach. By following specific strategies, one can effectively tackle these types of questions and improve their chances of scoring well. Here are some strategies to consider:

1. Understand the Concept:
Before attempting any question, it is crucial to have a clear understanding of the underlying concept. Review the relevant theory, definitions, formulas, and principles associated with the topic. This will provide a solid foundation for solving questions accurately.

2. Analyze Previous Years' Papers:
Thoroughly analyze previous years' papers to identify recurring question patterns, common derivations, and frequently asked theoretical calculations. This will help you prioritize topics and allocate time accordingly.

3. Practice Regularly:
Regular practice is key to mastering theoretical calculations and derivations. Solve a wide range of questions from previous years' papers, sample papers, and textbooks. This will familiarize you with different question formats and enhance your problem-solving skills.

4. Break Down the Question:
When encountering a question, carefully read and analyze it to identify the key components. Break down the question into smaller parts, highlighting the given information, required output, and any intermediate steps or assumptions needed.

5. Plan Your Approach:
Based on the question analysis, plan a step-by-step approach to solve it. This will help you stay organized and avoid mistakes. Decide which formulas, principles, or theorems are applicable and outline the logical sequence of steps required to reach the solution.

6. Show All Calculations Clearly:
While solving theoretical calculations or derivations, ensure that all calculations are shown clearly and neatly. Write down each step, including intermediate calculations, to demonstrate your understanding and provide a clear path to the final answer.

7. Review and Verify:
After solving a question, review your solution to check for any errors, inconsistencies, or omissions. Verify your answer with the expected result and cross-check with the given information to ensure accuracy.

8. Time Management:
Allocate time effectively to different sections of the question paper. Prioritize questions based on difficulty level and marks allotted. This will help you manage your time efficiently and attempt all questions within the given time frame.

Conclusion:
By following these strategies, you can improve your ability to solve questions involving theoretical calculations or derivations. Regular practice, thorough understanding of concepts, and proper time management are essential for success. Remember to analyze previous years' papers, break down questions, plan your approach, show calculations clearly, review your solutions, and practice regularly to enhance your problem-solving skills.