1. **State the problem:** We have 3 cups of cereal and 2 cups of cheese puffs in a snack mix. 2. **Part-to-part ratio of cheese puffs to cereal:** This ratio compares the amount of cheese puffs to the amount of cereal. $$\text{Cheese puffs : Cereal} = 2 : 3$$ 3. **Part-to-whole ratio of cheese puffs to total snack mix:** First, find the total cups of snack mix. $$\text{Total snack mix} = 3 + 2 = 5$$ Then, the ratio of cheese puffs to the whole snack mix is: $$\text{Cheese puffs : Snack mix} = 2 : 5$$ 4. **Proportion of cheese puffs to the whole as a fraction:** This is the fraction of cheese puffs out of the total snack mix. $$\text{Proportion} = \frac{2}{5}$$ This fraction is already in simplest terms because 2 and 5 have no common factors other than 1. **Final answers:** - Part-to-part ratio: $2:3$ - Part-to-whole ratio: $2:5$ - Proportion fraction: $\frac{2}{5}$