In a previous unit, students decomposed numbers to 20 in different ways. In previous lessons, students learned the meaning of each digit in a two-digit number. Students interpreted, used, and connected different base-ten representations for two-digit numbers including connecting cubes in towers of 10 and singles, base-ten diagrams, addition expressions, and written numbers.

In this lesson, students represent two-digit numbers in more than one way based on place value. Students learn that there are different ways to represent a two-digit number with tens and ones. Students extend this understanding in a later unit when they compose a ten to add within 100.

In the next unit, students add within 100, including adding numbers that require composing a new ten when adding by place. How will the work of this section prepare students for the upcoming work with addition?