Students use area diagrams and partial products to represent and find products of decimals.
In this culminating lesson on multiplication, students continue to use the structure of base-ten numbers to make sense of calculations (MP7) and consolidate their understanding of the themes from the previous lessons. They see that multiplication of decimals can be accomplished by:thinking of the decimals as products of whole numbers and fractions;writing the non-zero digits of the factors as whole numbers, multiplying them, and moving the decimal point in the product; representing the multiplication with an area diagram and finding partial products; andusing a multiplication algorithm, the steps of which can be explained with the reasonings above.