The purpose of this Warm-up is to elicit observations about possible unknown quantities in a situation and to make explicit that a variable can be used to represent such a quantity. The reasoning here builds on students’ previous work in using a “?” to represent an unknown value or quantity.
Tell students to close their books or devices (or to keep them closed). Arrange students in groups of 2. Introduce the context of daily reading routine or reading a certain number of pages regularly to finish a book. Use Co-Craft Questions to orient students to the context and elicit possible mathematical questions.
Give students 1–2 minutes to write a list of mathematical questions that could be asked about the situation before comparing questions with a partner.
Jada reads 25 pages of a book every day. After several days, she has read the entire book.
Invite several partners to share one question with the class and record responses. Ask the class to make comparisons among the shared questions and their own. Ask, “What do these questions have in common? How are they different?” Listen for and amplify language related to the learning goal, such as “how many days,” “how many pages,” and “how long.”
To connect the idea of an unknown quantity in a situation to a variable, display the equation 25n=200 for all to see and ask students:
If time permits, display another equation, 25t=50, and ask students:
Highlight that a variable can also be used to represent an unknown quantity in a situation, such as the number of days or the number of minutes in Jada’s reading example.
All skills for this lesson
No KCs tagged for this lesson
The purpose of this Warm-up is to elicit observations about possible unknown quantities in a situation and to make explicit that a variable can be used to represent such a quantity. The reasoning here builds on students’ previous work in using a “?” to represent an unknown value or quantity.
Tell students to close their books or devices (or to keep them closed). Arrange students in groups of 2. Introduce the context of daily reading routine or reading a certain number of pages regularly to finish a book. Use Co-Craft Questions to orient students to the context and elicit possible mathematical questions.
Give students 1–2 minutes to write a list of mathematical questions that could be asked about the situation before comparing questions with a partner.
Jada reads 25 pages of a book every day. After several days, she has read the entire book.
Invite several partners to share one question with the class and record responses. Ask the class to make comparisons among the shared questions and their own. Ask, “What do these questions have in common? How are they different?” Listen for and amplify language related to the learning goal, such as “how many days,” “how many pages,” and “how long.”
To connect the idea of an unknown quantity in a situation to a variable, display the equation 25n=200 for all to see and ask students:
If time permits, display another equation, 25t=50, and ask students:
Highlight that a variable can also be used to represent an unknown quantity in a situation, such as the number of days or the number of minutes in Jada’s reading example.