a way to remember which is the biggest is this little phrase.

king

henry

died

drinking

chocolate

milk

standing for

kilo

hecto

deca

[regular meter]

deci

centi

milli

so to convert anything you would just move the decimal place to either the right or left.

for more info check http://en.wikipedia.org/wiki/SI

Kilometers Hectometers Decameters meters Decimeters Centimeters Millimeters.

Now that you have the set up, its all a matter of which way you are going to move the decimal point in your number. Choose where your measurment is and count the hops to the next measurements and just move the decimal point in that direction for whatever number of hops you have counted.

for example you have 550 millimeters as meters. Start at millimeters and go left to meters. It is 3 jumps to the left to get to meters so you move the decimal point 3 spaces to the left giving you .550 meters.

you can do this for the rest of your measurements and you will get:

3.5seconds=3500 milliseconds

1.6kilograms=1600grams

2500milligrams=.002500kilograms

2800millimoles=2.8moles

6.1amps=6100milliamps

for the micro and nano units you are going to go two past milli. from meters it would be meters decimeters centimeters millimeters micrometers nanometers. as with the other measurments its all a matter of counting jumps and moving the decimal point in that direction for that many jumps.

so….

4 centimeters=400micrometers

3micrograms=30 nanograms

hope t his helped