Answer :
1 meter = 1000 millimeters
so, 5 meters = 5*1000 = 5000 millimeters
and 6000 millimeters = 6000 / 1000 = 6 meters
so, 5 meters = 5*1000 = 5000 millimeters
and 6000 millimeters = 6000 / 1000 = 6 meters