In this number talk, first grade teacher Liz O’Neill challenges her students to “Rename That Number,” finding different number sentences that represent the number 34 in as many ways possible. One student shares “5+5+5+5+5+5+2+2.” O’Neill leads the students in counting the addends, double-checking their skip-counting. Another student shares “30+4,” and a third shares “40-6=34.” O’Neill clarifies that in this task, the student doesn’t need to use the “=34” because all of these number sentences are ways of “renaming” 34. The fourth student to share says “3 tens and 4 ones.” O’Neill’s students count by tens and ones to confirm his strategy. This number talk is illustrative of Common Core mathematical practice standard 1 (“make sense of problems and persevere in solving them”), as the students make sense of the problem. They also show the ability to create coherent representations of the problem at hand (Common Core mathematical practice standard 2, “reason abstractly and quantitatively”).

Taught by: Liz O'Neill, M.H. Tobias Elementary School, Jefferson Elementary School District, Daly City, California

Mathematical Strands:

- Operations and Algebraic Thinking

- Number & Operations in Base Ten