Introduction:
The SBI PO Prelims and Mains Exams are conducted by the State Bank of India to recruit Probationary Officers. These exams assess the candidates' aptitude, reasoning, and English language skills. To ensure fair and standardized assessment, the use of certain materials such as rough paper and calculators may be restricted. Let's explore the rules regarding the use of these materials in detail.

Use of Rough Paper:
- Restrictions: As per the official guidelines of the SBI PO exams, candidates are not allowed to bring any rough paper or sheet to the examination hall. This rule is enforced to maintain the integrity and fairness of the examination process.
- Provided Material: However, candidates are provided with a rough sheet at the examination center. This sheet can be used for rough work and calculations during the exam. It is important to use this provided rough sheet wisely to manage time effectively.

Use of Calculator:
- Restrictions: The use of calculators is strictly prohibited in the SBI PO Prelims and Mains Exams. Candidates are expected to perform calculations manually without the aid of any electronic devices.
- Reasoning Behind the Rule: The ban on calculators is implemented to assess the candidates' mental math skills, calculation speed, and accuracy. These skills are considered essential for the role of a Probationary Officer, as they often deal with financial calculations and analysis.
- Preparation Strategy: To excel in the exams, candidates should focus on improving their mental math skills and quick calculations. Regular practice and familiarity with common mathematical operations, formulas, and shortcuts can significantly enhance their speed and accuracy.

Conclusion:
In summary, candidates appearing for the SBI PO Prelims and Mains Exams are not allowed to bring rough paper or calculators to the examination hall. However, they are provided with a rough sheet for calculations during the exam. The ban on calculators is to assess the candidates' mental math skills, which are crucial for the role of a Probationary Officer. Therefore, candidates should focus on practicing mental math techniques and improving their calculation speed to perform well in these exams.