Short Answer 
To create a mixture, measure out 2/3 cup of toothpaste and use 3/4 cup of coconut oil to maintain the correct proportions. This means for every 1/3 cup of toothpaste, 1/4 cup of coconut oil is needed.
Measure the Toothpaste
Start by measuring out 2/3 cup of toothpaste. This amount will serve as the base for calculating how much coconut oil you will need. It’s important to ensure that your measuring tools are accurate to get the correct proportions for your mixture.
Calculate the Coconut Oil
Next, understand the relationship between the toothpaste and coconut oil. For every 2/3 cup of toothpaste, you will need 1/2 cup of coconut oil. When you split these amounts in half, you get:
- 1/3 cup of toothpaste corresponds to 1/4 cup of coconut oil.
Combine for Final Measurement
Since there are 3 parts of 1/3 cup in a full cup, you can now determine the total amount of coconut oil you need by multiplying:
- 3 (from 1/3) x 1/4 cup = 3/4 cup of coconut oil.
This means that to match the 2/3 cup of toothpaste, you will ultimately be using 3/4 cup of coconut oil.