This figure shows the four units km, m, cm, and mm in four bubbles. Arrows show that to change km into m, you multiply by 1000; to change m into cm, you multiply by 100 and to change cm into mm, you multiply by 10. Further arrows show that to convert mm into cm, you divide by 10, to convert cm into m, you divide by 100 and to convert m into km, you divide by 1000.