Multiply Fractions Game Day

10 min

Narrative

The purpose of this Number Talk is to elicit strategies and understandings students have for multiplying fractions. These understandings help students develop fluency and will be helpful later in this lesson when students will need to multiply fractions.

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.

  • 13×3\frac{1}{3}\times3
  • 13×4\frac{1}{3}\times4
  • 13×63\frac{1}{3}\times\frac{6}{3}
  • 13×14\frac{1}{3}\times\frac{1}{4}

Sample Response

  • 1: I just knew it.
  • 1131\frac{1}{3}: 33=1\frac{3}{3}=1 and there is one more third.
  • 23\frac{2}{3} or 69\frac{6}{9}: 13×2=23\frac{1}{3}\times2=\frac{2}{3}
  • 112\frac{1}{12}: I multiplied the denominators.
Activity Synthesis (Teacher Notes)
  • Display: 13×63\frac{1}{3} \times \frac{6}{3}
  • “How did you find this product?” (I took the products of the numerators and denominators. I knew 63\frac{6}{3} is 2, so it’s 23\frac{2}{3}.)
Standards
Addressing
  • 5.NF.4·Apply and extend previous understandings of multiplication to multiply a fraction or whole number by a fraction.
  • 5.NF.B.4·Apply and extend previous understandings of multiplication to multiply a fraction or whole number by a fraction.

15 min

20 min