Rank longest to shortest

1Mm, 1km, 100m, 1cm, 50mm, 1mm, 5 million nm

this is the order i came up with and its wrong .. what i did was try to convert them all to meters than rank them , but it still wrong

50mm = 5cm

so put 50mm in front of 1 cm

5 million nm would be 5 mm too

so put 5 million nm before 1 mm