I need help in chemistry about metric system prefixes and stuff, i don't get? here the problem...?

1). how many watts are in one megwatt? (2).how many gram are in four kilogram? (3).what fraction of a joule is one millijoule? (4).what fraction of a second is 1 picosecond? (5.)1centimeter=___ meter. ( 6).1__liter=0.001 liter (7)1 microgram=___gram. ( 8)1__volt=1000 volts.