In this activity students do a little comparison shopping as they determine which size Goldfish product is the best deal. Students are introduced to the ratio table as a tool for determining equivalent ratios and comparing different rates. Students graph cost per ounce relationships and answer a few open questions, which should lead to some good thinking and discourse in this authentic math activity.
Consider bringing in a big bag of Goldfish for the class to snack on while they work on the activity. It will then truly be yummy math. Check out a second version of the activity (scroll down in the post) that solely focuses on and makes a connection between the ratio standards in grades six and seven.
Addressed CCSS: 5.G.2, 6.RP.1, 6.RP.2, 6.RP.3, 6.NS.2, 7.RP.2, 7.RP.3, 8.EE.5
For members we have an editable Word doc and solutions and tips.
Goldfish-cheesy.doc Goldfish_solutions.pdf
We have a second version of the Goldfish problem that is meant to only focus on standards 6.RP.3 and 7.RP.2 . The task gives the costs of various cheese goldfish products at one store and asks students to compare the three products price per ounce or ounce per price in order to see which one is the best deal. This task connects back to standard 6.RP.3 having student intuitively working through a ratio table to find various price and ounce relationships for each product. Students are asked to find a unit rate of either ounces based off one dollar or dollars based off ounces. This could lead to rich conversation as students define and graphically represent unit rate in two different ways. The activity ends with an open question that asks students to come up with a possible product that offers a better value than any of these products.
And solutions: Goldfish-solutions-7RP26RP3.pdf