In this lesson, students build on work done in previous grades with numbers in base ten. They use base-ten diagrams to represent different powers of 10 and review how multiplying and dividing by 10 affect the decimal representation of numbers. They use their understanding of base-ten structure as they express very large and very small numbers using exponents.

Students also practice communicating— by describing and writing—very large and small numbers, which requires attending to precision (MP6). This leads to a discussion about how powers of 10 can be used to more easily communicate such numbers. Students do not need to read or write numbers in formal scientific notation, as that will be introduced in a following lesson. The focus here is on introducing the idea that numbers can be written as a multiple of a power of 10 and to practice doing that flexibly.