Ratio, Rate and Percent
One number compared against a chosen base, written as a fraction, a rate or a percent. Speed, density, discount, interest and concentration are all the same move -- decide what the base is, divide by it, and read the answer as a comparison. The work in these problems is almost never the arithmetic; it is identifying which quantity is the base.
grade 6–7 Ratios Analyze the UnitsIdentify Subproblems
Progression (8)
g6 1. A rate is the ratio written as a number RatiosExpressions
g6 2. A rate gives the area of a part RatiosGeometry
g6 3. A percent is a rate out of 100 Ratios
g6 4. Speed is distance over time Ratios
g6 5. Population density is people over area Ratios
g7 6. Discount rate is the discount over the original price Ratios
g7 7. Interest rate is interest over principal Ratios
g7 8. Concentration is salt over solution Ratios