Lesson 14

The purpose of an Estimation Exploration is to practice the skill of estimating a reasonable answer based on experience and known information. If needed, discuss what a food drive is in the launch of the activity.

• Groups of 2
• Display image.
• If necessary, “What is a food drive?”
• “What is an estimate that’s too high? Too low? About right?”
• 1 minute: quiet think time

• “Discuss your thinking with your partner.”
• 1 minute: partner discussion
• Record responses.

• “Is anyone’s estimate less than ___? Is anyone’s estimate greater than ___?”
• “Based on this discussion does anyone want to revise their estimate?”

The purpose of this activity is for students to apply their understanding of place value and properties of operations to solve two-digit addition real world problems (MP2). Students may use any method and representation that helps them make sense of the problems in context.

• Groups of 2
• Give students access to connecting cubes in towers of 10 and singles.
• “The table shows the number of cans four students collected for their class’ food drive.”
• “What do you notice? What do you wonder?” (They collected a lot of cans. Tyler collected the most. Han collected the least. I wonder how many they collected all together.)

• Read the task statement.
• 6 minutes: independent work time
• “Check in with your partner. Be prepared to show or explain your thinking.”
• 5 minutes: partner discussion

• Invite students to share the equations that show the total number of cans or display: \(42 + 43 = 85\) and \(54 + 31 = 85\)
• “Many of you used these two equations to find how many cans were collected by all four students.”
• “What are the similarities and differences?” (Both equal 85 and use the same information about four students, but each number represents the total for two different students.)
• “What other equations can we use to find the total number of cans collected by all four students?” (\(18 + 24 + 13 + 30=85\), \(48 + 24 + 13=85\))

The purpose of this activity is for students to find pairs of numbers that have a value that is between 35-65. Some students may use trial and error to solve the problem. Encourage students to consider a strategic way to determine if a combination of two classes may or may not meet the constraint. For example, students may notice that combining 1st and 2nd grade will not work because 5 tens and 2 tens is 7 tens which is more than the 65 can limit.

• Groups of 2
• Give students access to connecting cubes in towers of 10 and singles.
• “The whole school is collecting cans for a food drive. This table shows how many cans each grade collected on the first day of the food drive. The cans are brought down to the main office so the student council can pack them into boxes.”

• Read the task statement.
• 10 minutes: partner work time
• Monitor for 2-3 partnerships who determine different box arrangements.

• Invite previously identified students to share.
• Record responses.
• “Is this statement true? 6th grade’s cans can be packed with any other grade level.” (Yes, since they only collected 8 cans and the highest amount of cans collected was 51 in 1st grade. \(51 + 8 = 59\), which is still under 65 cans.)