If the number is 15,_56 where a single digit (0-9) goes in that blank space, then the possible answers are: 0, 1 ,2, 3, or 4.
The thousands place is the first 5 shown in the given number. The digit just next to that will determine how we round. This digit is in the hundreds place. If the hundreds digit is between 0 and 4, then we replace every digit after that first 5 with 0s. So we go from 15,_56 to 15,000
If the hundreds digit is 5, 6, 7, 8, or 9, then we round up to the nearest thousand to jump up to 16,000. This is because something like 15,556 or 15,656 is much closer to 16,000 than 15,000
