This video includes the basics of doing conversions, why conversions work, conversions with squares and fractions. Includes several examples.

Times of the examples:
0:59 - 11 millimeters to meters
2:54 - 4.2 cm to m
3:35 - 17 g to kg
4:32 - 14 m/s to km/hr
7:40 - 12.2 mm^2 to m^2
9:50 - 120 km/hr^2 to m/s^2