Write the given number in roman system.
90

Answer

To convert the number 90 into the Roman numeral system, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Roman Numerals**:
- The Roman numeral system uses letters from the Latin alphabet to represent values. The key letters include:
- I = 1
- V = 5
- X = 10
- L = 50
- C = 100

2. **Identify the Components of 90**:
- The number 90 can be expressed as 100 - 10.
- In Roman numerals, 100 is represented by 'C' and 10 is represented by 'X'.

3. **Apply the Subtractive Notation**:
- In Roman numerals, when a smaller numeral appears before a larger numeral, it is subtracted.
- Therefore, to represent 90, we write 'C' (for 100) and place 'X' (for 10) before it to indicate subtraction.

4. **Write the Roman Numeral**:
- Putting it all together, we write 90 in Roman numerals as 'XC'.

### Final Answer:
- The Roman numeral for 90 is **XC**.