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: 
Solve quadratic equations in one variable.

Answer: 
Yes. This task shows one quadratic equation with 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: 
Construct a tangent line from a point outside a given circle to the circle.

Answer: 
No. This task does not involve drawing lines that are tangent to circles. The only line that may be drawn is the ray between points P and B.

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_pos_0

HS_1

im_task_001160_neg_0

HS_2
standard_description: Fluently add and subtract within 20 using mental strategies. (See standard 1.OA.6 for a list of mental strategies.) By end of Grade 2, know from memory all sums of two one-digit numbers.
problem_activity: Narrative
The purpose of this activity is for students to create their own relevant mathematical questions and use their understanding of addition and subtraction to answer questions about their own and their peers' survey data.
Launch
Combine pairs into groups of 4
Activity
“Switch graphs. Use the sentence stems or create your own questions about the other group’s graphs.”
1
–
2 minutes: independent work time
4 minutes: partner work time.
“Take turns to ask each other the questions you came up with and use your own graph to answer.”
“When possible, write down an equation to show your reasoning.”
5 minutes: group discussion.
Monitor for students who write equations to show the categories they combine or compare when answering their peers' questions.
Student Facing
Trade graphs. Create questions about the other group’s graph.
Sentence stems:
How many students picked ___________ and __________ all together?
How many more students picked _______ than _______?
Take turns asking and answering questions.
Student Response
Teachers with a valid work email address can
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for free access to Student Response.
Advancing Student Thinking
If students rely on counting to find solutions rather than adding or subtracting, consider asking "What equation could you write to represent the categories in the question?"
Activity Synthesis
Invite previously selected students to share.
“Where do we see the equations in their graph? What does the equation mean?”
“What’s the difference between answering the questions from a bar graph and answering them from a picture graph?”


aligns: yes