standard_description: Derive using similarity the fact that the length of the arc intercepted by an angle is proportional to the radius, and define the radian measure of the angle as the constant of proportionality; derive the formula for the area of a sector.
problem_activity: Narrative
The purpose of this activity is for students to fluently add and subtract within 5. Students look at the expression on their card and move quickly to the corner that is labeled with the correct answer. There are 16 expression cards included in the blackline master.
MLR8 Discussion Supports.
Invite students to read the expression card aloud to each partner. Listen for and clarify any questions about the the expressions.
Advances: Conversing
Required Materials
Materials to Gather
Materials from a previous lesson
Required Preparation
Each student needs one card from the Expression Cards set used in a previous lesson.
Label each corner of the classroom with a large number: 2, 3, 4, and 5.
Launch
Give each student an expression card.
“Find the value of the expression on your card. Go to the corner that is labeled with the value of the expression.”
Activity
30 seconds: independent work time
“Find a partner in your corner. Show them your card and tell them how you found the value of your expression.”
2 minutes: partner discussion
“Walk back to the center of the room. Trade your card with a partner.”
Repeat the steps above 3–4 times, as time allows.
Activity Synthesis
Display the expression
\(3 - 1\)
.
“Noah saw this expression and went to the corner labeled 4. Was he correct? How do you know?” (No, because this is 3 take away 1 and that is 2.)
“Why do you think he went to the corner labeled 4?” (He might have thought it was
\(3 + 1\)
instead of
\(3 - 1\)
.)


aligns: no