# Math help - page 2

1. Thread moved to Nursing Student Assistance forum, thanks to all who have replied with helpful advice!
2. Quote from cvinson30
Ok the question is if you have Bicillin 1,200,000/2ml and the doctor orders 600,000, how many mls do you give. I did 600,000/1,200,000 and got 0.5 and then did 0.5 mutiplied by 2ml and got 1ml. So is this right and is so I do the same process if the doctor orders 900,000 right?
You are making this way more complicated than it needs to be. You have 1,200,000 units in 2 mL. In your head you should be able to figure out that that means you have 600,000 units in 1 mL and then you don't even have to do any further math to get your answer.
3. OP, when faced with similar questions in the future, just disregard the zeroes and focus on the whole numbers instead...until you become more familiar with calculating dosages. When you reach your final answer, replace the zeroes in your equation if you must show your work.

Set up your equation using the whole numbers:
Step #1. 12mg is in 2ml.
Step #2. Ordered amount is 6mg.
Step #3. If the doc ordered 6 to be given from a total of 12, basic math tells us to split the total amount (2ml) in half, which is 1ml....[since you've already been given the answer] ;-)

Some of these should come easily if you look at the whole numbers instead of all of the zeroes. However, you need to learn to calculate the dosages as it is written because it can make a world of difference and mean life or death if you forget to include those zeroes where they need to be, especially if there are decimals leading the zeroes.
4. Quote from KelRN215
You are making this way more complicated than it needs to be. You have 1,200,000 units in 2 mL. In your head you should be able to figure out that that means you have 600,000 units in 1 mL and then you don't even have to do any further math to get your answer.
Think of it this way - you have 1,200,000 cherry jelly beans in a big bag. You have to eat 600,000 of them.

How much of that bag full are you going to eat?
5. Proportions equation!!!! very helpful way to calculate proportions. Once you learn it, you'll use it forever.
http://syzygy.virtualave.net/mf_graphics/propor.gif

a/b = c/d
so a= b*c/d
b = a*d/c
c = a*d/b etc

this is easier to see when they're written out across each other. Soo....
Quote from cvinson30
<u>120000</u> = <u>2 mL</u>
600000 x

x = (600000*2)/120000
6. learn to calculate proportions, it will come in handy ... a lot.
If 1 pant is 2 pantlegs, then how many pants is 7 pantlegs?

1 pant= 2 pantlegs
x pants 7 pantlegs
1 = 2
x 7

x = 7*1/2= 3.5

how many pantlegs in 12 pants?
1 pant = 2 pantlegs
12 pants x pantlegs

x= 12*2/1

(sorry here 1/x and 2/7. Don't know how to do proportions in html)

google/youtube whatever proportion calculations and you'll learn a very useful way of calculating meds!
7. Just learn simple dimensional analysis and you can do dosage problems, IV drip problems, percent problems, mEq problems.

600,000 mg (2 mL/1,200,000 mg) =1 mL