How do i round 299,792,458 into only 3 significant digits?

You can not round a million to a hundred. You have to keep the numbers value place. And when you do, it rounds to
300,000,000 depending on where you round it. In this case I rounded it in the millions place. If you rounded it, in the thousands place it would be 299,790,000 or 299,800,000. Hope you understand.

No table found. the question asks for covalent bond based on electronegativies