**Reason Abstractly and Quantitatively**

1st Grade

Mathematically proficient students in First Grade continue to develop their ability to clearly express, explain, organize and

consolidate their math thinking using both verbal and written representations.

consolidate their math thinking using both verbal and written representations.

- Their understanding of grade appropriate vocabulary helps them to construct viable arguments about mathematics.
- For example, when justifying why a particular shape isn’t a square, a first grade student may hold up a picture of a rectangle, pointing to the various parts, and reason, “It can’t be a square because, even though it has 4 sides and 4 angles, the sides aren’t all the same size.”
- In a classroom where risk-taking and varying perspectives are encouraged, mathematically proficient students are willing and eager to share their ideas with others, consider other ideas proposed by classmates, and question ideas that don’t seem to make sense.