Lesson: Perfect Ice

Play the video “When Water Freezes.” Then, before or after reading the article, spark a discussion based on the following questions:

• Can ice come in different sizes and forms? Explain.
• What are some measurements that would be recorded during Winter Olympic sporting events?

• What strategies or models can we use to multiply numbers? (repeated addition, arrays, area models, standard algorithm, partial products)
• Do you think we can use any of these to help us multiply fractions? Explain. (Answers will vary.)
• Today we will use the standard algorithm to multiply fractions by whole numbers.
• Play the video “Multiplying Fractions.”

• What do you notice about the repeated addition equation? (You are adding the same fraction, ²/₅ , 10 times)
• How do we rewrite a whole number as a fraction? (place the whole number in the numerator and 1 in the denominator)
• Why should we not leave the answer as ²⁰/₅ ? ( ²⁰/₅ is an improper fraction and can be simplified)
• How do we simplify  ²⁰/₅ ? (Answers will vary. Possible answers: Divide the numerator and denominator by the greatest common factor, 5. So ²⁰/₅ simplifies to ⁴/₁ which is equal to 4; divide 20 by 5.)

Have students complete problems 1 through 4 on page 11 of the article.

Skills Sheets: Level Down: Multiplying Fractions by Whole Numbers With Number Lines (4.NF.B.4) | On Level: DynaDash: Multiplying Fractions by Whole Numbers (5.NF.B.4) | Level Up: Fraction Division Story Problems (5.NF.B.3)

SEL (Social-emotional learning activity/prompt): In this article, students learned how Mark Messer takes pride in getting the ice just right for each event, which has led to several records being set. Have students think about something they have accomplished or take pride in. Allow students to share their accomplishments with the class.

Dynamath@Home: Have students look up a recipe for their favorite dish that includes at least 2 fractions. Ask them to pretend they are creating this recipe for a very large group of people. Then have students create a shopping list of the items they will need by multiplying each ingredient by 4 to quadruple the recipe.