Question

Which is greater 6km or 54,000 mm

Answer 1

1 km is 1,000,000 mm. So 6k is the equivalent of 6,000,000 mm.  So 6km > 54,000mm 

Answer 2

1 km = 1,000,000 millimeters
6 km = 6 * 1,000,000 millimeters = 6,000,000 mm

6,000,000 mm is greater than 54.000 mm

Therefore, 6 km is greater than 54,000 mm,