The large quantities involved in these questions lend themselves to multiplication and division with powers of 10. Students use numbers and exponents flexibly and interpret their results in context (MP2). 

The goal of this discussion is for students to share their strategies for multiplying and dividing with numbers written as a multiple of a power of 10.  Begin by inviting students to share how they used the information to answer the questions. Here are some additional questions for discussion:

• “Were the results of your calculations surprising? Why?” (Answers vary.)
• “How did powers of 10 make the calculations simpler?” (There were fewer zeros and shorter expressions to work with.)

As students share their reasoning and strategies, make sure all students understand the following examples:

• To find the product of and , we can write because and .
• To find the quotient of and , we can write because and .

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Invite 2–3 students to share the norm they chose and how it supported the work of the group or a realization they had about a norm that would have worked better in this situation. Provide these sentence frames to help students organize their thoughts in a clear, precise way:

• “I picked the norm ‘.’ It really helped me/my group because .”
• “I picked the norm ‘.’ During the activity, I realized the norm ‘’ would be a better focus because .”
   

This optional activity further illustrates the utility of using powers of 10 to work with and interpret very large quantities. Students practice modeling skills, such as identifying essential features of a problem and gathering the required information (MP4). 

The goal of this discussion is for students to see how powers of 10 can be a useful strategy when dealing with problems that involve very large numbers. Begin by inviting students to share how they used the information to answer the question. Here are some questions for discussion:

• “Were the results of your calculations surprising? Why?” (Answers vary.)
• “How did powers of 10 make the calculations simpler?” (There were fewer zeros and shorter expressions to work with.)

It might be illuminating to put 35 million light years into some context. It is over a thousand trillion times as far as the distance to the Moon, or about the size of a supercluster of galaxies. The Sun is less than  light year away from Earth.