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”).
1st Grade Math - Rename That Number
Liz O'Neill, M.H. Tobias Elementary School, Jefferson Elementary School District, Daly City, California
LIZ O'NEILL: Omar, can you share with us what you did?
STUDENT: 5...plus 5, plus 5, plus 2, plus 2.
LIZ O'NEILL: Wow! Let's see how many addends you have.
STUDENTS: 1, 2, 3, 4, 5, 6, 7, 8.
LIZ O'NEILL: Let's double-check this. 5, 10...
STUDENTS: 15, 20, 25, 30, 32, 34.
LIZ O'NEILL: Isabella, what do we have?
STUDENT: Um, 30 plus 4.
LIZ O'NEILL: 30 plus 4. Do we agree that 30 plus 4 is 34?
LIZ O'NEILL: All right. High five in the air to Izzy. Isabelle, what do you have for us?
LIZ O'NEILL: 40.
STUDENT: Minus 6 equals 34.
LIZ O'NEILL: Okay. So we could say 40 minus 6 equals 34, or I could even just say 40 minus 6 because I'm renaming that number. It's like a name collection box.
LIZ O'NEILL: Oh! So when you started at 40 and you counted back...where did you end up? Awesome! High five in the air to Isabelle. Eric, what did you tell me?
LIZ O'NEILL: Three tens, and four ones. Let's count by tens and ones to make sure we do come up with 34.
STUDENTS: 10, 20, 30, 31, 32, 33, 34.
LIZ O'NEILL: Very nice. Okay. High five in the air to everybody.