In this activity, students work with customary units of capacity for liquids (gallon, quart, and cup). The task prompts them to discern the relationship between the units, express the relationships with multiplicative comparison statements, and perform conversions to solve problems. When they identify the relationship between gallons, quarts, and cups, students reason abstractly and quantitatively (MP2).

To compare quantities given in different units, students choose which unit to use for comparison and consider the implications of their choice. Students likely will convert a value in a larger unit to a value in a smaller unit (from gallons and quarts to cups), but some may reason the other way around (from cups and quarts to gallons, ending up with fractional amounts). In grade 4, students are expected only to convert from a larger unit to a smaller one.

MLR8 Discussion Supports.  To support the transfer of new vocabulary to long-term memory, invite students to chorally repeat these words or phrases in unison 1–2 times: “gallon,” “quart,” “cup.”
Advances: Representing, Speaking, Listening

• Poll the class on the unit they used to compare the amounts of lassi.
• Select a student who chose each option to share the rationale behind their decision.
• Display the table, with an extra column for showing the amounts in cups.
• Invite students to share their responses to the questions about lassi and their reasoning, completing the table along the way.

  guest	amount of lassi	amount of lassi (cups)
  Priya	10 cups	10
  Uncle	3 quarts	12
  Cousin	8 cups	8
  Grandma	2 gallons	32

• Highlight that converting the amounts into the same unit helped us: see the greatest amount, find the total amount, and see how many times as much lassi one guest made compared to another guest.
• To reinforce students' understanding of the relationship between the units of capacity used here, consider creating a diagram as shown:

  

• “How does the diagram show that 1 gallon is 4 times as much as 1 quart and 16 times as much as 1 cup?”

In this activity, students convert units of weight—pounds and ounces—and use multiplicative reasoning to solve problems about weight. As in the prior activity, students can choose to reason in either of the two units, but the given quantities encourage conversion from pounds to ounces.

This activity uses MLR6 Three Reads. Advances: reading, listening, representing.

• Select students to briefly share their responses and their reasoning.
• “Did anyone reach the same conclusion but reasoned in a different way?”