Students often think additively rather than multiplicatively. For example, if you present the scenario, "One puppy grew from 5 pounds to 10 pound. Another puppy grew from 100 pounds to 108 pounds." and ask, "Which puppy grew more?" someone who is thinking additively will say that the one who now weighs 108 grew more because he gained 8 pounds while the other gained 5 pounds. Someone who is thinking multiplicatively will say that the one that now weighs 10 pounds grew more because he doubled his weight while the other only added a few pounds. While both are correct answers, multiplicative thinking is needed for proportional reasoning. If your students are thinking additively, you can nudge them toward multiplicative thinking with this activity.

In this lesson designed to enhance literacy skills, students learn how to use fractions to interpret the nutritional information contained on food labels.

In some textbooks, a distinction is made between a ratio, which is assumed to have a common unit for both quantities, and a rate, which is defined to be a quotient of two quantities with different units (e.g. a ratio of the number of miles to the number of hours). No such distinction is made in the common core and hence, the two quantities in a ratio may or may not have a common unit. However, when there is a common unit, as in this problem, it is possible to add the two quantities and then find the ratio of each quantity with respect to the whole (often described as a part-whole relationship).

A very short video introduction to how photosynthesis cycles energy through an ecosystem and a "real-world" application of ratios! Lindsay Hollister, JPPM's horticulturalist, taps a black walnut tree for its sap and park staff boil it down to create syrup. Included in this video are an animated food web showing the directions of energy flow during photosynthesis and when sap is "rising," which can be extended by students to include humans or more parts of their local ecosystem. Use the video as an introduction to activities about sugar and biological storage, and an excuse to sample maple syrup to taste the sugar. Alternatively, research trees nearby students could help tap and witness the biological transfer of energy themselves.

Always be sure you can successfully identify a plant before using it and take precautions to avoid negative reactions.

This resource is part of Jefferson Patterson Park and Museum’s open educational resources project to provide history, ecology, archaeology, and conservation resources related to our 560 acre public park. More of our content can be found here on OER Commons or from our website at jefpat.maryland.gov. JPPM is a part of the Maryland Historical Trust under the Maryland Department of Planning.

This lesson unit is intended to help teachers assess how well students are able to solve a real-world modeling problem. There are several correct approaches to the problem, including some that involve proportional relationships.

In this lesson designed to enhance literacy skills, students examine how to use fractions to measure and help conserve freshwater resources.

This is the first and most basic problem in a series of seven problems, all set in the context of a classroom election. Every problem requires students to understand what ratios are and apply them in a context. The problems build in complexity and can be used to highlight the multiple ways that one can reason about a context involving ratios.

This is the second in a series of tasks that are set in the context of a classroom election. It requires students to understand what ratios are and apply them in a context. The simple version of this question just asked how many votes each gets. This has the extra step of asking for the difference between the votes.

This problem, the third in a series of tasks set in the context of a class election, is more than just a problem of computing the number of votes each person receives. In fact, that isnŐt enough information to solve the problem. One must know how many votes it takes to make one half of the total number of votes. Although the numbers are easy to work with, there are enough steps and enough things to keep track of to lift the problem above routine.

This is the fourth in a series of tasks about ratios set in the context of a classroom election. What makes this problem interesting is that the number of voters is not given. This information isnŐt necessary, but at first glance some students may believe it is.