Lesson 12: Applications of Arithmetic with Powers of 10 | Unit 7: Exponents and Scientific Notation

Open Ended

Which is larger: the number of meters across the Milky Way, or the number of cells in all humans? Explain or show your reasoning. Some useful information: * The Milky Way is about 100,000 light years across. * There are about 37 trillion cells in a human body. * One light year is about $$10^{16}$$ meters. * The world population is about 8 billion.

Multiple Choice

What information would you need to know in order to solve the following problem? Suppose that someone leaves all the lights on at your school. Before leaving for the day, the principal goes around and turns off all the lights. How long does this take?

• The principal must check if the lights are working before turning them off.
• The time taken is the same regardless of the number of lights.
• The principal needs to know the total number of students in the school.
• The time taken depends on the number of lights and the time per light.

Open Ended

Lin’s mother has a car that she uses for work, shopping, and trips. About how many times does one tire on her car revolve in a year? Explain or show your reasoning. Some useful information: * The diameter of her tire is 27 inches. * She drives about 10,000 miles in one year. * There are 5,280 feet in one mile. * There are 12 inches in one foot.