# Med Math Question?

1. Hi guys,

So today I had a med math quiz, and I had trouble with a conversion question. The question was something along the lines of "Ordered 62.5 mcg and available 0.5 mg/mL. How many mL will be administered?".

Any help is appreciated!!
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2. ### About nrsgstudnet1

Joined: May '18; Posts: 3; Likes: 1

3. Was it something along the lines of or was that the exact question? (Math is precise)

Why don't you show us what you think first- and then we can help you VS. just doing it for you.
4. Hi,

As far as I remember (we aren't allowed to take the quizzes home), this was the exact question.

Here was my thought process:
Converted the 62.5 mcg to mg to get 0.0625 mg
Then I set up the formula to cross multiply 0.0625mg/x multiplied by 0.5mg/1mL
I got 0.5x = 0.0625
Divided 0.0625 by 0.5
My final answer = 0.125 mL

I know I don't use the same method as some do, but this is how it makes sense to me.

Thanks again!
5. Hi Nrsgstudnet1,
The way you set it is is called ratio proportion. I prefer a method called dimensional analysis. You are starting with 62.5 mcg and have to change that mL of the 0.5 mg/mL solution. You don't have to pre-convert anything doing it this way. 62.5 mcg (1 mL/0.5 mg)(1 mg/1000 mcg) = 0.125 mL. If you learn this method, you can use it for unit conversions, dosage calculations, and IV Flow Rate Problems. You should take a lot at my article in the pre-nursing section: Master Your Drug Calculations Before You get to Nursing School. You will also find a helpful book there.
Master Your Drug Calculations BEFORE You Get to Nursing School
6. Thank you, the link is helpful!

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