We are taking extra time on this unit because the idea of a ratio progresses from 6th grade through freshman algebra where it becomes a linear model. I can tell you from experience that linear models are a huge part of the algebra 1 curriculum. A solid conceptual understanding and procedural fluency will increase the likelihood of success in future years.
And looking to college and careers later, it is important to consider that ratios and proportions are also a very common type of problem found on standardized tests like the SAT.
Here is a very brief tour of the progression of the idea of a ratio from 6th grade to high school algebra and then high school geometry.
6th grade
Ratio Tables
Double Number Lines
Tape Diagrams
Rates
Scale Factors/Scale Drawings
7th Grade
Ratios as Multiplicative Relationships Not Just Parallel Skip Counting
Constant of Proportionality
Graphing Proportions
8th grade and Algebra 1
Full Blown Linear Models
Extensions to High School Statistics
Extensions to High School Geometry: Similar Shapes
As you can see, ratios and proportions are a big deal and it is a good idea to make sure we get them right.
