Double Number Lines

Different Ways to Represent Ratios

Formative Assessment

Summary of the Math: Different Ways to Represent Ratios

Read and Discuss

  • You can use both tape diagrams and double number lines to show ratios.
    • This tape diagram shows that the ratio of pints of red paint to pints of blue paint in a paint mixture is 4:7.
    • Thus, one way to produce a mixture with the correct ratio is to mix 4 pints of red paint with 7 pints of blue paint.
  • You can use a double number line if you want to show many different ways to mix the paint and still get the same ratio of red to blue (and thus the same final paint color).
    • This double number line shows that you can mix 4 pints of red paint with 7 pints of blue paint, or 8 pints of red paint with 14 pints of blue paint, or 12 pints of red paint with 21 pints of blue paint, and so on.
    • You will still get a paint mixture that has a 4:7 ratio of red paint to blue paint.

Can you:

  • Explain how to use tape diagrams to represent ratios?
  • Explain how to use double number lines to represent ratios?