Common Core Standards: Math
2. Recognize and represent proportional relationships between quantities.
We don't hear Superman complaining about having X-ray vision, but there's a way more useful kind of math-vision for seventh graders: the ability to see proportions. Knowing whether two fractions, ratios, or sets of quantities are proportional to each other is an essential skill your students will be building on for years to come, and we're not just saying that. Anytime your students rock a linear function, cross-multiply to solve for a variable, reduce a fraction, or puzzle through a percentage problem, they'll be using proportions in some way.
This standard has four different parts: testing out two quantities to see if they're proportional, tracking down the constant of proportionality (and knowing its relationship to a unit rate), transforming verbal proportions into equations, and navigating graphs of proportional relationships. They might not become super-powered crime-fighters or anything, but once students get this standard under their belts, they'll be unstoppable proportion-solving machines.
Let's just hope they use their powers for good and not for evil.
LinksRatios and Proportional Relationships Worksheet 2
Ratios and Proportional Relationships Worksheet 2 – Solutions