Which of the following is not defined?

Options

A. `5 + 0`
B. `5 - 0`
C. `5 xx 0`
D. `5 div 0`

Answer

To determine which of the following operations is not defined, we will evaluate each option step by step.

### Step-by-Step Solution:

1. **Evaluate Option 1: 5 + 0**
- When we add 5 and 0, the result is:
\[ 5 + 0 = 5 \]
- This operation is defined.

2. **Evaluate Option 2: 5 - 0**
- When we subtract 0 from 5, the result is:
\[ 5 - 0 = 5 \]
- This operation is also defined.

3. **Evaluate Option 3: 5 × 0**
- When we multiply 5 by 0, the result is:
\[ 5 \times 0 = 0 \]
- This operation is defined as well.

4. **Evaluate Option 4: 5 ÷ 0**
- When we attempt to divide 5 by 0, we need to consider the rules of division. Division by zero is not defined in mathematics because there is no number that can be multiplied by 0 to yield 5. Therefore:
\[ 5 \div 0 \text{ is not defined.} \]

### Conclusion:
- Among the options, the only operation that is not defined is **Option 4: 5 ÷ 0**.

### Final Answer:
- The answer is **Option 4: 5 divided by 0**.

---