Number talks were developed for classroom teachers to engage students in "mental math" through grappling with interesting mathematics problems. Educators can use number talks regularly as introductions to the day’s mathematical practice, as “warm ups” for other lessons, or as standalone extended engagements with mathematical concepts.
2nd grade: Number of the Day
In this Number Talk, Stephanie Letson engages her 2nd grade students in finding multiple ways to write equations that result in the number 170. She introduces her students with some norms for their learning, such as listening, sharing, writing. She introduces the day’s number by asking them what they notice about the number, and what those noticings (multiple of ten, even number) might mean for their equations. Students work individually, then share in small groups, then share as a whole group. Letson facilitates their discussion and follows student insights when they are offered.

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2nd grade: ¿Cómo se suma?/ How do we add?
In this Number Talk, Katy Arrillaga engages her 2nd grade Spanish bilingual students in a discussion about strategies for mentally solving a problem involving twodigit addition with regrouping. The students share their strategies and evaluate each other’s approaches for solving the problem.

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4th grade: Can This Be True?
In this Number Talk, Elysha Passeggi engages her 4th grade students in a discussion about whether or not the sum of two twodigit numbers can be 238. Students share their responses, defend their thinking, and formulate declarative statements about why the problem is definitively false.

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5th/6th grade: Guess My Rule
In this Number Talk, Fran Dickinson engages his 5th and 6th grade students in divining the function from the input and output numbers. As the learners guess input numbers, the educator generates the output number. After each guess he has one of the learners “graph the point."

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7th grade: What’s the Savings?
In this Number Talk, Debbie Borda and Antoinette Villarin engage their 7th students in mentally calculating the savings received by a student who paid $54 for an item that was discounted 40%. The students in the class first think their way through the problem, then share their strategies with a partner, then share strategies and answers with the class as a whole.

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