In the second grade, students work with numbers up to 1000. In this grade, they expand their place value understanding to multi-digit whole numbers up to a million. Therefore, they work on thousands and hundred thousand. While dealing with numbers up to a million, students also need to work with comma to separate the intervals (thousand, hundred thousand and million).

Common Core Alignment

4.NBT.1Recognize that in a multi-digit whole number, a digit in one place represents ten times what it represents in the place to its right.