few_shots: 
Example 1:
Problem/activity:
Find the general solution for:
$${\mathrm{cos}\left({\pi\over2}+x\right)=\mathrm{tan}{\pi\over4}}$$


Concept/skill: 
Prove the addition and subtraction formulas for sine, cosine, and tangent and use them to solve problems.

Answer: 
Yes. An initial step when solving for x in this problem requires the use of the addition formula for cosine on the left side of the equation.

Example 2:
Problem/activity:
Task
Solve the quadratic equation
$$ x^2 = (2x - 9)^2 $$
using as many different methods as possible.


Concept/skill: 
Understand that the graph of an equation in two variables is the set of all its solutions plotted in the coordinate plane, often forming a curve (which could be a line).

Answer: 
No. This task does not involve an equation in two variables. There is only one variable, x.

Example 3:
Problem/activity:
Task
Suppose $A$ is an angle with vertex $P$, as pictured below:
[IMG]
Draw a circle with center $P$ and with  radius $r \gt 0$.  Explain why the circle
meets each ray of angle $A$ in a single point.  Label these points $Q$ and $R$ respectively.
Draw circles with centers $Q$ and $R$ respectively and radius $r$.  These circles meet at $P$ and a second point to be labelled $B$.
Show that ray $\overrightarrow{PB}$  bisects angle $P$.


Concept/skill: 
Make formal geometric constructions with a variety of tools and methods (compass and straightedge, string, reflective devices, paper folding, dynamic geometric software, etc.). Copying a segment; copying an angle; bisecting a segment; bisecting an angle; constructing perpendicular lines, including the perpendicular bisector of a line segment; and constructing a line parallel to a given line through a point not on the line.

Answer: 
Yes. This task asks students to draw a ray that bisects an angle. The act of drawing circles and rays may involve compass and straightedge or dynamic geometric software.

Now, assess whether the following problem or activity is 'aligned' with the given Common Core standard in Mathematics.

shot_info: fl_problem_001894_pos_0

HS_0

im_task_000870_neg_0

HS_1

im_task_001160_pos_0

HS_2
standard_description: Fluently add and subtract within 100 using strategies based on place value, properties of operations, and/or the relationship between addition and subtraction.
problem_activity: Narrative
The purpose of this activity is for students to connect story problems to the equations that represent them and to solve different types of story problems. Students identify equations with a symbol for the unknown that match a story problem and justify their decisions by describing how the equations represent the quantities and any actions in the story problem (MP4). When students analyze and connect the quantities and structures in the story problems and equations, they are thinking abstractly and quantitatively (MP2) and making use of structure (MP7).
MLR8 Discussion Supports.
Display sentence frames to support discussion as students explain their reasoning to their partner: “I noticed ___ , so I matched . . .” Encourage students to challenge each other when they disagree.
Advances: Conversing, Representing
Required Materials
Materials to Gather
Base-ten blocks
Materials from a previous lesson
Materials to Copy
Equations for Different Types of Word Problems
Required Preparation
Create a set of cards from the blackline master for each group of 2
–
4.
Each group of 2
–
4 needs a set of cards from the previous lesson.
Launch
Groups of 2
–
4
Give each group the story problems (Cards A–I) from the Story Problem and Diagram Cards.
Give one set of Equation Cards to each group of students.
Give each group access to base-ten blocks.
“Take turns reading the story problems. After one person reads, work together to find an equation that matches. When you think you have found a match, explain to your group why the cards match.”
“If you think that more than one card could match the story, explain the match to your group.”
As needed, demonstrate the activity with a student volunteer.
“When your group finishes, choose 2 story problems from Cards F, G, H, or I and solve them.”
Activity
6 minutes: partner work time
Monitor for students who explain why more than one equation may match a story and how the equations match the quantities in the context of the story problem.
4 minutes: independent work time
Student Facing
Match each story problem with an equation. Explain why the cards match.
Choose 2 story problems and solve them. Show your thinking.
Student Response
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Advancing Student Thinking
Students may believe that only one equation could match each story. Encourage
students to describe how equations match any actions in the story and whether any other equations show the same actions. If there are no actions in the story, ask students to explain why one or more cards shows the relationship between the parts and the whole. Consider providing the tape diagrams from the previous activity to support students in their explanations.
Activity Synthesis
Invite students to share a match for each story.
Consider asking:
“How does the equation match the story problem?”
“Is there another equation that could match the story problem? Explain why or why not.”


aligns: yes