Notice that in the number 7952, the column of the "thousands" is that occupied by the number 7.
I order to round it to the thousands', we need to write ONLY a representing number in that column and zeros in the other following three columns.
Notice as well that the number 7 is followed bi a number 9 in the column of the hundreds. then we round the 7 to the following integer (8), and write:
7952 rounded to the nearest thousand is 8000