Decompose teen numbers as 10 ones and some ones; compare some ones to compare the teen numbers.

In this lesson, students work to count to tell the number of objects by answering "how many?" questions. They compare teen numbers by counting and comparing the extra ones. For example, students decompose 12 into 10 and 2, and 16 into 10 and 6. They compare 2 ones and 6 ones to see that 16 is more than 12 using the structure of the 10 ones.