Learning Context:

Students will learn equivalent fractions by using proportions to find the amount of baking soda needed to change the pH level of a 10-gallon tank of water to the appropriate level for the tilapia fish.
Students will calculate the number of ounces in one gallon and then find the number of ounces in 10 gallons.
Students will find the amount of baking soda needed to change the pH level in a
4 ounce vial of the same fish tank water, and use a proportion to find the amount of baking soda needed to change the pH of the 10 gallon tank to the appropriate level.

Learning Standard   #3
Numbers and operations

NYS Standards
Standard 3: Mathematics
Number Operations: Students use number sense and numeration to develop an understanding of the multiple uses of numbers in the real world, the use of numbers to communicate mathematically, and the use of numbers in the development of mathematical ideas.
Key Ideas:

• Students understand and apply ratios, proportions, and percents through a wide variety of hands-on explorations

http://matti.usu.edu/nlvm/nav/frames_asid_105_g_3_t_1.html

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http://bluebin.com/article_beginning.shtml#reference

http://www.elmhurst.edu/~chm/vchembook/184ph.html