Let's evaluate each statement one by one.
1. **3×10×10×10=3×10^3**
- The left side simplifies to \(3 \times 10^3\), which is equal to the right side.
- **Answer**: Yes
2. **400,000=4×10^6**
- The left side, 400,000, can be expressed as \(4 \times 10^5\) (not \(4 \times 10^6\)).
- **Answer**: No
3. **7×10^5=7×100,000**
- The left side is \(7 \times 10^5\) and \(10^5\) is equal to 100,000. Thus, both sides are equal.
- **Answer**: Yes
4. **5 × 1,000=5,000**
- The left side simplifies to \(5 \times 1000\), which is equal to 5,000.
- **Answer**: Yes
So the final answers are:
1. Yes
2. No
3. Yes
4. Yes