IV Compounding Math Question: How is a Tic Tac Toe Board Used In This Example?

by Sherri
(Raleigh NC USA)

An order for 6 liters of 0.9% soium chloride solution is to be prepared from 23.4% concentrated NaCl solution and sterile water for injection.How many mL of each will be used?

The answer is supposed to be 231 mL of 23.4% and 5769 mL of water but I can't seem to figure out how they got their answer or what formula they used. What is the tic tac toe board supposed to look like? Do I multiply by 6, 6000, or 1000? or do i do the usual cross multiply and divide with the 1000?

Comments for IV Compounding Math Question: How is a Tic Tac Toe Board Used In This Example?

Average Rating starstarstarstarstar

Click here to add your own comments

Tic Tac Toe Board and Answer...
by: Robert

This Pharmacy IV Math question can be solved by using the Tic Tac Toe Board. Using the amounts supplied, the board would be set up as follows:

Middle square – 0.9

Top left square – 23.4

Bottom left square – 0

Following the instructions, subtract the amount in the middle square from the top left square – 23.4% - 0.9% = 22.5% - and this amount goes in the bottom right square. Do the same thing with the middle left and bottom left square – 0.9% - 0 = 0.9% and put this amount in the top right square. Next add the top right and bottom right numbers – 22.5 + 0.9 = 23.4. The answers are then multiplied by the volume needed, which is 6 liters or 6000 milliliters.. 6000 multiplied by 0.9 divided by 23.4 equals 231 ml of concentrated NACL. 6000 – 231 = 5769 ml of sterile water.

Here is an example of how to set up a Tic Tac Toe Board to aid in finding the answer to solution preparation.

Use a regular Tic Tac Toe Board that you can simply draw on a piece of paper. In the middle square of the board write the desired strength. In the top left square, place the higher strength solution. In the bottom left square, place the lower strength unless you are using water in which case this number would be a zero.

Subtract the amount in the middle square from the amount in the top left square. Put this number in the bottom right square, then subtract the amount in the middle square from the bottom left square and put this amount in the top right square.

Add the numbers in the top and bottom right squares and divide the top right number and the bottom right number by this amount. Multiply each answer by the volume needed and the result will be how much is needed of each solution. To make certain it is the right answer, add the two and it should be equal to the total volume.

You will find the majority of the time the Tic Tac Toe Board will help you to find the right solution. Because practicality dictates that it is easier to dilute than to compound preparations, alligation is the method used for solving these problems when mixing different strength products. Using a Tic Tac Toe Board for the process is one of the simplest ways of doing so.

I hope this solution will help you.
by: Anonymous

1. 23.4%-0.9% = 22.5%
2. 0.9%-0=. 0.9%

Total quantity you get is 0.9+22.5= 23.4
So 6000ml of 0.9 is 6000*0.9\23.4= 231 ml
231ml is concentrated NACL solution. To find out sterile water we subtract
6000ml - 231 ml= 5769 ml sterile water.

Click here to add your own comments

Join in and write your own page! It's easy to do. How? Simply click here to return to Pharmacy Tech Math Questions.

Back to Home

[?]Subscribe To This Site
  • follow us in feedly
  • Add to My Yahoo!

Didn't find what you were looking for? Use the box below to search this entire site.

Custom Search

Recent Articles

  1. What is day supply take 1 tab on tues and thurs with 30 tabs

    Dec 04, 18 09:06 PM

    What is day supply if I take 1 tablet on Tuesday and Thursday with a quantity of 30 tabs?

    Read More

  2. DUR Rejection Codes

    Nov 27, 18 11:16 PM

    DUR Rejection Codes - Conflict Codes, Professional Service Codes, Result of Service Code, & Level of Effort Field

    Read More

  3. How Does Nalexone Nasal Spray Help an Overdose Victim?

    Nov 23, 18 08:43 PM

    This page discusses, "How Does Nalexone Nasal Spray Help an Overdose Victim?"

    Read More

  4. Medicare Part D

    Jul 31, 18 10:26 PM

    This page answers questions about Medicare Part D, the prescription drug benefit offered by Medicare. Topics include: Who is eligible? What are some of the Costs? Factors to Consider when choosing a p…

    Read More

  5. What are some strategies the FDA has implemented, which help prevent medication errors in the pharmacy?

    Jul 29, 18 06:23 PM

    It seems like some of the errors that have been recently made by our pharmacy techs are actually really preventable. Does the FDA do anything about

    Read More

  6. Osmolarity/Hospital Potassium Infusion problem (3 Part Question)

    Jul 29, 18 05:24 PM

    At 3:00 P.M., a pharmacist received an order to add 30 mEq/L of potassium chloride to the already running intravenous fluid for a patient. After checking

    Read More


    Jul 29, 18 05:12 PM

    My pharmacy tells me I can get it 3 days early but then they wont fill it but 2 days early. Is the law on Xanax 2 or 3 days ?

    Read More

  8. pharmacy technician exam

    Jul 13, 18 10:36 PM

    I am looking for a tutor to help me prepare for the pharmacy technician certification exam. I live in area code 85373. Can anyone recommend a tutor?

    Read More

  9. Bromfenac(bromday) 0.09% When can I get a refill?

    Jul 13, 18 10:25 PM

    I am to instill 3 drops into both eyes 3 times a day. Received prescription, of 3 bottles/vials, on 16 Mar 18 and need to know how to figure how long

    Read More

  10. Is Publicly mentioning the name of the drug the patient is on a HIPPA violation?

    Jul 13, 18 10:17 PM

    If the name of the drug is mentioned in order to further assist the patient with getting them the medication, is this a violation of hipaa?

    Read More

  11. What is a "Root Cause Analysis"? And how does a pharmacy create "healthy safety culture"?

    Jul 13, 18 09:56 PM

    Recently there was a wrong-drug mistake at the pharmacy I'm employed at as a technician. One of my tech friends (who works at a different pharmacy) asked

    Read More

  12. What is the Correct Dosage for Protamine Sulfate After Receiving 3,000 units of Heparin?

    Jun 28, 18 11:01 PM

    The intern sent the following orders down: Mr. Brown, 50 mg protamine sulfate STAT. You check Mr. Brown’s chart, and he received 3,000 units of heparin.

    Read More

  13. Prior Authorization Rejection

    Apr 10, 18 11:13 PM

    This page covers what a Prior Authorization is and why it happens.

    Read More

  14. My 10 yr olds prescription -- Is The Following Situation a HIPPA Violation?

    Apr 10, 18 10:00 PM

    I know someone who is a pharmacy tech. My 10yr.olds medication was called into the pharmacy she works at. Her daughter and my daughters have an on-off

    Read More

  15. My Pharmacy told my mom that I didn't pick up my meds. Is this a Hippa Violation?

    Apr 10, 18 09:26 PM

    My pharmacy told my mom I didn't pick up my meds. Yes, I do have same last name but I have a different address; for all they know, that wasn't my mom.

    Read More