lesson
Updated 6 days ago · 3 views
Imagine you want to mix the perfect shade of lime green slime. Every recipe calls for exactly 2 scoops of blue powder for every 3 scoops of yellow powder.
A ratio is a comparison of two quantities by division, showing how much of one thing relates to another.
📊A clean visual diagram showing two groups of colored circular counters on a light gray card. Left group: 2 blue circles labeled '2 Blue'. Right group: 3 yellow circles labeled '3 Yellow'. Between them, a clean label shows the ratio written three ways: '2 to 3', '2 : 3', and '2/3'. Below, a total bracket groups all 5 circles together, labeled 'Total: 5 scoops'. High contrast colors (#2563eb blue, #eab308 yellow, #1e2945 text, #f8f9fa card background), rounded corners, smooth styling.
Can we compare these same scoops to the whole recipe instead of just to each other?
Part-to-Part vs. Part-to-Whole
When you compare blue scoops to yellow scoops (2:3), you are writing a part-to-part ratio.
When you compare blue scoops to all scoops combined (2:5), you are writing a part-to-whole ratio.
📊A side-by-side comparison diagram showing Part-to-Part vs Part-to-Whole. Left panel: 'Part to Part' with 2 blue squares and 3 yellow squares, text showing 'Blue to Yellow = 2 : 3'. Right panel: 'Part to Whole' with 2 blue squares out of a 5-square strip, text showing 'Blue to Total = 2 : 5 (or 2/5 of the mix)'. Clean responsive layout, clear card borders (#e2e8f0), dark text (#1e293b).
Counters work great for small batches, but how do we draw ratios when the numbers get bigger?
Strip Models (Tape Diagrams)
A strip model (or tape diagram) uses identical rectangular blocks to represent equal parts of a ratio.
If each block represents 4 ounces of liquid, then 2 blue blocks hold 8 ounces, and 3 yellow blocks hold 12 ounces.
📊A tape diagram with two horizontal bars made of equal-sized connected square units. Top bar has 2 blue blocks, each labeled '4 oz', with a bracket labeled 'Blue = 8 oz'. Bottom bar has 3 yellow blocks, each labeled '4 oz', with a bracket labeled 'Yellow = 12 oz'. A right-hand bracket wraps both bars together showing 'Total = 20 oz (5 units × 4 oz)'. Crisp modern design with responsive layout under 350px width.