Pharmacy Tech Math - Alligation tutorial

Alligation math is a little known short-cut used by pharmacy techs and pharmacy students. It's also known popularly in pharmacy tech school as tic-tac-toe math.

Here's the next steps in how to work an alligation:

( Cont'd from previous page )

Step #4

So, now the amounts of the differences you found become the "Parts" of the % directly across the grid from it.

alligation math

Parts of the 3%

 → Parts of the 1%

Step #5

On your paper, write

Parts of  ___%


Add up the total "Parts"

Step #6

Now, take a look back at the question and look for the total volume needed.

On your paper, to the left of number of parts, write

the needed volume


A division sign 

Step #7

Alligation Directions

Do the Math:

Now, you've divided the final solution volume into "Parts".

In this case, there's 125mL per part.

Step #8

Now, go back up to the "parts" and write the volume per part.

The Answer:

The question asked how much 3% to use. So, that's :1 part X 125mL =

125mL of the 3%

Here's what your paper should look like when done

Now, go to:

 Alligation Math II - additional explanation

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