Number Talk

10 min

Narrative

The purpose of this Number Talk is for students to demonstrate strategies and understandings they have for finding whole-number quotients of whole numbers with up to four-digit dividends and two-digit divisors. These understandings help students develop fluency and will be helpful later in this lesson when students will develop their own Number Talk activity.

Launch

  • Display the first 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.

  • 28÷1428\div14
  • 70÷1470\div14
  • 98÷1498\div14
  • 350÷14350\div14

Sample Response

  • 2: 2×14=282\times14 = 28.
  • 5: 14×10=14014\times10=140, so 14×5=7014\times5=70.
  • 7: 98=28+7098 = 28 + 70, so 98÷14=(28÷14)+(70÷14)98\div14 = (28 \div 14) + (70 \div 14).
  • 25: 14×20=28014\times20=280 and 14×5=7014\times5=70 and 280+70=350280+70=350.
Activity Synthesis (Teacher Notes)
  • “What did the writer of this activity have to pay attention to when they designed this activity?” (The values of the expressions need to be found mentally, so they can't be too complex.)
  • “Where do we see those things in how the expressions change during the Number Talk?” (The first expression helps to do the second one, and the first 3 help to do the last one.)
  • “Imagine this Number Talk continued with a fifth expression. How does 700÷28700 \div 28 fit in with this Number Talk?” (It doubles the dividend and the divisor from the previous expression, which means the quotient is the same, 25.)
Standards
Addressing
  • 5.NBT.6·Find whole-number quotients of whole numbers with up to four-digit dividends and two-digit divisors, using strategies based on place value, the properties of operations, and/or the relationship between multiplication and division. Illustrate and explain the calculation by using equations, rectangular arrays, and/or area models.
  • 5.NBT.B.6·Find whole-number quotients of whole numbers with up to four-digit dividends and two-digit divisors, using strategies based on place value, the properties of operations, and/or the relationship between multiplication and division. Illustrate and explain the calculation by using equations, rectangular arrays, and/or area models.

15 min

15 min

15 min