Which of the following Roman numerals are not valid? State the reason for your answer in each case.
XVVI

Answer

To determine whether the Roman numeral "XVVI" is valid, we will analyze it step by step.

### Step 1: Identify the components of the Roman numeral
The Roman numeral "XVVI" consists of the following letters:
- X = 10
- V = 5
- V = 5
- I = 1

### Step 2: Check for repetition rules
In Roman numerals, certain letters have specific rules regarding how many times they can be repeated:
- The letter "V" can only appear once in a valid Roman numeral. It cannot be repeated.

### Step 3: Analyze the numeral "XVVI"
In "XVVI," the letter "V" appears twice. This violates the rule that states "V" cannot be repeated.

### Step 4: Conclusion
Since "V" is repeated in "XVVI," this Roman numeral is not valid.

### Final Answer
The Roman numeral "XVVI" is not valid because the letter "V" is repeated, which is against the rules of Roman numeral formation.

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