How Do You Convert mg to kg?

[r-soy]

Hi

I want help to convert mg to kg

ex: 1250mg --- > kg

Are we multiply 1250mg X 10^-3

or multiply 1250mg X 10^-6


I want your help >>

 

[granpa]

http://www.wolframalpha.com/input/?i=1250mg+in+kg

 

[The legend]

wolframalpha's real good!

 

[granpa]

http://www.wolframalpha.com/input/?i=metric+prefixes

 

[phyzguy]

One way that I've found helps students that are new to unit conversions understand is called "multiplying by 1" In any expression, I can multiply by 1 as many times as I want without changing the answer. To see how this works, let's take you question, as follows:
$$1250 mg = 1250 mg \frac{1 g}{1000 mg} \frac{1kg}{1000g} = \frac{1250 kg}{10^6} = 1250 \times 10^{-6} kg$$

Does this help? The problem with Wolfram Alpha is that, while it works, you don't usually know what it is doing.