Students begin to see a ratio as both the comparison of two quantities and as a number in its own right. In a social studies unit, students use population and area data for countries in South America to compute population densities, and then compare their results to those for other areas of the world. Students use two different sizes of grid paper to copy a simple drawing of a house from the smaller grid to the larger grid, investigating and discussing the change from one to the other and exploring ways to represent it numerically. They then copy the same drawing onto a third grid, smaller than the second but larger than the first. As follow-up, they invent other closeness problems for each other.
Students search for as many uses of percent as they can find over the course of a week.
The sources for the uses, however, are to be exclusively within the school setting. Develop and use order relations for integers and rational numbers. Students use a deck of fraction cards for a variety of tasks. Determine which pairs have a value close to 1. Students use a number line, including both positive and negative integers, to graph inequalities stated verbally.