Number Talk

10 min

Narrative

The purpose of this Number Talk is to elicit the strategies and understandings students have for adding within 1,000. These understandings help students develop fluency and will be helpful when students create their own Number Talk routines.

In the Activity Synthesis, discuss what students know about the Number Talk routine and what they need to think about to create a routine like the example.

Launch

  • Display one expression.
  • “Give me a signal when you have an answer and can explain how you got it.”
  • 1 minute: quiet think time
Teacher Instructions
  • Record answers and strategies.
  • Keep expressions and work displayed.
  • Repeat with each expression.

Student Task

Find the value of each expression mentally.

  • 300+400300 + 400
  • 300+437300 + 437
  • 321+437321 + 437
  • 425+514425 + 514

Sample Response

  • 700: I know that 400 plus 300 is 700. I just know it.
  • 737: I added the hundreds to get 700 and there are 37 more, so the sum is 737.
  • 758: I added the hundreds to get 700, the tens to get 50, and the ones to get 8, and then the sum is 758.
  • 939: I added the hundreds, the tens, and then the ones to get 939.
Activity Synthesis (Teacher Notes)
  • “What do you know about the Number Talk routine?” (It always has 4 expressions, and we find their values in our head. Sometimes we can use the same method for each expression. Sometimes we can use the first couple of expressions to help us find the values of other expressions.)
  • Consider asking: “What would you have to think about if you were going to design a Number Talk like this one?” (How one expression might relate to the next. What strategies might make it possible for someone to find the values mentally. Whether it's possible to use one expression to find the values of other expressions.)
  • Record and display responses for all to see.
Standards
Addressing
  • 3.NBT.2·Fluently add and subtract within 1000 using strategies and algorithms based on place value, properties of operations, and/or the relationship between addition and subtraction.
  • 3.NBT.A.2·Fluently add and subtract within 1000 using strategies and algorithms based on place value, properties of operations, and/or the relationship between addition and subtraction.

15 min

15 min

15 min

15 min