1 kilometer is equal to how many meters, centimeters, and millimeters?

Answer 1

1km = 1000 meters
Each meter has 100 cm.
Each cm has 10 mm.

If you post your answer, we'll be glad to check it for you.

Answer 2

1 km = 1,000 meters, 100,000 cm, and 1,000,000 mm?

Answer 3

Looks good to me. Here is a site that may be of help to you.
http://physics.nist.gov/cuu/Units/prefixes.html