I am confused and need some help with this math question.

0The client with lung cancer is 1 day postop lobectomy and demonstrates symptoms of infection. The health care provider orders 900 mg of Nafcillin. There is powder in a vial labeled "Nafcillin 1 gram" with instructions "to dilute with 3.4 mL of sterile water to produce 1 gram in 4 mL.".
How many milliliters does the nurse administer? (Round to the nearest tenth and write only the number.)
**please let me know some simple steps on how you got the answer. Maybe i am studying too much and my brain is burning out 


Nov 21, '12 by NursingBrothis is what it says :(4 mL/1 gram) X (1 gram/1000 mg) X (900 mg/1) = 3600/1000 = 3.6 mL

Nov 21, '12 by SaoirseRNYes, that's the answer I got.
To make this really simple, you need to find out how many mg/ml the solution is.
1000mg/4ml equals 250mg/ml
You need 900mg. How many times does 250 go into 900?
900/250= 3.6 
Nov 22, '12 by NursingBroI dont know what is wrong with me sometimes I just cant see it.
one way i was doing it is 900 / 1000 = 0.9 0.9 x 4 = 3.6
another weird way is 900 x 4 = 3600 3600/1000 = 3.6
do you know a website that can help me out with the math? It is tough for me to see it in my mind. 
Nov 22, '12 by PalmHarborMomI am in nursing school at the University of South Florida. We use the book Calculating with Confidence 5th Edition by Gray Morris. The book has a website There is some great info on doing calculations and practice problems. You do need to register.Last edit by Esme12 on Nov 27, '12 : Reason: TOS/link removed

Nov 22, '12 by loriangel14 GuideI use Doc (what the doctor ordered) over stock ( what you have on hand) 900/1000 = 0.9.Multiplied by the volume(4) = 3.6


Nov 22, '12 by Esme12, ASN, BSN, RN Senior ModeratorYou may find this website helpful.
DosageHelp.com  Helping Nursing Students Learn Dosage Calculations 
Nov 22, '12 by NursingBroQuote from Esme12Great website! thanks!You may find this website helpful.
DosageHelp.com  Helping Nursing Students Learn Dosage Calculations 

Nov 23, '12 by mariebailey, MSN, RNSome simple steps:
1. Don't forget to convert your g to mg.
2. Remember the Mass/Liquid for Liquid Formula (found on site previously posted)
Ordered X Volume have = Liquid Required Have 
Nov 26, '12 by BloomNurseRNI use a similar method to Loriangel14.
Desired dose/Have * Quantity = X (D/H * Q = X)
Desired (900 mL)/Have (1000 mL) * 4 mL = 3.6 mL
Good luck!