Lesson objective: Understand that we can generate hypotheses about the likelihood of an event by counting possible outcomes and favorable outcomes.

Students bring prior knowledge of part-to-part and part-to-whole comparisons from 6th Grade (6.RP.A.1). This prior knowledge is extended to reasoning about the likelihood of a random event as students count and compare outcomes. A conceptual challenge students may encounter is thinking that the outcome of a random event is purely based on luck and cannot be predicted through reasoning.

The concept is developed through work with a probability line, which shows the continuum of likelihoods from impossible to certain.

This work helps students deepen their understanding of number because they compare the number of chances for a specified outcome to the number of chances for other outcomes, or the total number of possible outcomes.

Students engage in Mathematical Practice 3 (Construct viable arguments and critique the reasoning of others) as they explain their reasoning about why their mixes of gumballs support Paige's prediction.

**Key vocabulary:**

- certain
- impossible
- likely
- outcomes
- possible
- unlikely

**Special materials needed:**

- (optional) Coloring supplies could enhance student work, enabling students to show their gumball mixes in color, though they could also describe the mixes in words