Which of the following is not a Euclid's axiom?

Options

A. The whole is greater than the part.
B. Things which are double of the same things are equal to one another.
C. Things which are halves of the same things are equal to one another.
D. If two things are equal, then their sum is equal to of the one thing.

Answer

To determine which of the following statements is not a Euclid's axiom, we need to analyze each option provided.

### Step-by-Step Solution:

1. **Identify the Options**:
Let's assume the options are:
- Option 1: The whole is greater than the part.
- Option 2: Things which are double of the same thing are equal to one another.
- Option 3: Things which are half of the same thing are equal to one another.
- Option 4: If two things are equal, then their sum is equal to that of one thing.

2. **Analyze Each Statement**:
- **Option 1**: "The whole is greater than the part."
- This is known as the fifth axiom of Euclid.
- **Option 2**: "Things which are double of the same thing are equal to one another."
- This corresponds to the sixth axiom of Euclid.
- **Option 3**: "Things which are half of the same thing are equal to one another."
- This is the seventh axiom of Euclid.
- **Option 4**: "If two things are equal, then their sum is equal to that of one thing."
- This statement does not correspond to any of Euclid's axioms.

3. **Conclusion**:
After analyzing all the options, we find that **Option 4** is not a Euclid's axiom.

### Final Answer:
The correct answer is **Option 4**.