Hi there!
To Round of the number given, first you have to find the ten thousands place on the given number. Started from ones, tens, hundreds, and moving on, the number in the ten thousands place would be 7 in your case.
Now, looking to the number on the right of 7 which is 8, it is bigger than 5, and therefore, we round up 7 and let 8 go to zero.
Applying this, your answer would be 4,280,003
Hope this helped!