Help with unit conversion?? PLEASE!!?

Question

i need help with unit conversions (obviously)

how can i remember how much to multiply and/or divide to get to the unit that i want to convert to?? (did this make sense)

like i know grams and meters is the base and then theres milli, deci, centi etc.

and in order to convert from (for example) millimeter to meters you would have to multiply or divide by 10 or 100 or 1000

and how do i use conversion factor?

OR if there is a really good website i could use that too

thanks!!

Answer 1

It takes a little longer, but I never use shortcuts when I'm doing conversions because I tend to slip up and make mistakes, so I write everything out.

For example, if I wanted to convert 7 millimetres to kilometres, I'd write it all out with all the equivalences and cancel them out until I reach the unit I need.  ie:

#km = 7mm x 1cm/10mm x 1m/100cm x 1km/1000m = 7x10^-6km

See how the mm, cm, and m units cancel out?

I don't know if that's the best explanation, but that's how I do it.