• Revise their answer after examining Kiran’s mistake.
• Recognize that so must be greater than 5,850.
• Can explain why Kiran should be multiplying .
• Recognize that , so there should be three zeros in the second partial product.

When students determine Kiran's error and make sense of his work, they interpret and critique the work of others (MP3).

• Ask previously identified students, as described in the Activity Narrative, to share their thinking.
• Display Kiran's work.
• “Why doesn’t 5,850 make sense?” ( so should be greater than 6,500.)
• “What makes sense about Kiran’s work?” (. , but he needs to multiply .)
• Display a student's correct solution or the image from Student Responses.
• “How do we know that 17,550 is a reasonable value for the product?” (because )

The purpose of this activity is for students to practice multiplying multi-digit numbers that have one or more digits of 0 at the end. Monitor for students who:

• Use the standard algorithm to find the value of .
• Multiply the product by 10 to find the value of the product .
• Multiply the product of by 10 to find the value of the product .

Students who observe that and and use these relationships to find the values of the products are observing regularity in repeated reasoning and using their knowledge of how to multiply a whole number by 10 (MP7, MP8).

• Display the product .
• Ask previously identified students to share their solutions.
• Display correct student work or the image from Student Responses:

  

• “What is the relationship between and ?” (The product is 10 times as great as because one of the factors is 10 times greater.)
• “What is the relationship between and ?” (The product is 100 times as great as  since 6,700 is .)