Factorial Meaning:
Factorial is a mathematical operation denoted by the exclamation mark (!). It is used to calculate the product of all positive integers from 1 to a given number. For example, the factorial of 5 (written as 5!) is calculated as 5 x 4 x 3 x 2 x 1 = 120.

Methods to Solve Questions on Number System:

1. Prime Factorization Method:
- Prime factorization is a method used to express a number as the product of its prime factors.
- To solve questions on the number system using prime factorization, follow these steps:
- Identify the given number and prime factorize it.
- Express the number as the product of its prime factors.
- Use the prime factors to find the required information.

2. Divisibility Rules:
- Divisibility rules are a set of rules that help determine if a number is divisible by another number without performing division.
- Some common divisibility rules include:
- A number is divisible by 2 if its units digit is even (0, 2, 4, 6, or 8).
- A number is divisible by 3 if the sum of its digits is divisible by 3.
- A number is divisible by 5 if its units digit is either 0 or 5.
- Apply the relevant divisibility rule to solve questions on the number system.

3. Factorization Method:
- Factorization is the process of expressing a number as the product of its factors.
- To solve questions on the number system using factorization, follow these steps:
- Identify the given number and factorize it.
- Express the number as the product of its factors.
- Use the factors to find the required information.

4. Number Series Method:
- Number series is a sequence of numbers in a specific pattern.
- To solve questions on the number system using the number series method, observe the pattern in the given series and find the next number or missing number in the series.
- Some common number series patterns include arithmetic series, geometric series, and Fibonacci series.

5. Percentage Method:
- The percentage method involves solving questions on the number system using percentages.
- To solve such questions, convert the given number or quantity into a percentage and use the percentage to find the required information.
- Apply the relevant percentage formulas and concepts to solve the questions.

By applying these methods, you can effectively solve questions on the number system in banking exams. Practice these methods regularly to improve your problem-solving skills and accuracy.