The purpose of this activity is for students to add and subtract fractions and estimate sums and differences of fractions, using the context of a recipe. Students may have different responses and reasoning for the estimation questions. In both cases, they can calculate and compare fractions, but they may have different thoughts about how these differences would affect the recipe or what exactly it means for the recipe to make “about cups.” In the Activity Synthesis, students discuss the reasonableness of the estimates and how to make precise calculations (MP6). When students relate their calculations to Priya's salad dressing, they reason abstractly and quantitatively (MP2).

• “If Priya borrows a tablespoon of olive oil from her neighbor and uses it to make dressing, will she be putting in more or less olive oil than the recipe calls for?” ( is smaller than so she will be putting in less olive oil.)
• “Do you think 1 tablespoon is close enough?”
• Poll the class.
• “How might Priya’s decision to use 1 tablespoon of olive oil change the salad dressing?” (It won’t make a difference because the difference is so small. It might taste more lemony or more mustardy because there is not as much oil. It might affect the consistency of the dressing a little.)
• Ask previously selected students to share their estimates for the amount of salad dressing in the given order.
• “Why might Priya estimate that the recipe makes  cups of salad dressing?” ( is away from 1 and is close to .)
• “Does the recipe make more than or less than cups? How do you know?” (More, because is more than .)
• “How many cups does Priya’s recipe make? How do you know?” (, I added , , and .)