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: Determine the unknown whole number in a multiplication or division equation relating three whole numbers. For example, determine the unknown number that makes the equation true in each of the equations 8 × ? = 48, 5 = �� ÷ 3, 6 × 6 = ?.
problem_activity: Narrative
The purpose of this activity is for students to practice division within 100 by playing a game called Race to 1. The goal of the game is to repeatedly divide numbers until they reach one.
Engagement: Develop Effort and Persistence.
Check in and provide each group with feedback that encourages collaboration and community.
Supports accessibility for: Social-Emotional Functioning, Organization
Required Materials
Materials to Gather
Number cubes
Launch
Groups of 2
“Take a minute to read the directions for Race to 1.”
1 minute: quiet think time
“Let’s look at a sample game. Jada rolled a 3 on her first turn, then rolled 2 a few times afterwards. Talk with your partner about what her next move should be if she rolls 2 on her next turn.” (She should divide 4 or 6 by 2 because those moves get her really close to one.)
1 minute: partner discussion
Share responses.
Give each group a number cube.
Activity
“Play Race to 1 with your partner.”
10–15 minutes: partner work time
If students finish early, have them play again. Students can fill in the same numbers from the first game at the top of the columns of the second game or use the numbers 24, 36, 48, and 72 for a challenge.
Student Facing
Directions for Race to 1
On your first turn:
Roll a number cube. The number you roll is your divisor. (If you roll a 5, roll again.)
Choose one number from the top row of your table. Divide it by your divisor.
Write a division expression and record the quotient in the table. Your turn is done.
On all your other turns:
Roll a number cube. The number you roll is your divisor. (If you roll a 5, roll again.)
Choose either a quotient from one of your past turns or a new number from the top row of the table. Divide it by your divisor.
Write a division expression and record the quotient in the table.
The first player to get a quotient of 1 wins.
Sample Game
Jada rolled 3 on her first turn, then rolled 2 a few times afterwards.
|    start number     |     12      |     16      | 18 |     24      |
|---------------------|-------------|-------------|----|-------------|
| division expression | \(12\div3\) | \(16\div2\) |    | \(24\div2\) |
|      quotient       |      4      |      8      |    |     12      |
| division expression |             |             |    | \(12\div2\) |
|      quotient       |             |             |    |      6      |
| division expression |             |             |    |             |
|      quotient       |             |             |    |             |
Game 1
|    start number     | 12 | 16 | 18 | 24 |
|---------------------|----|----|----|----|
| division expression |    |    |    |    |
|      quotient       |    |    |    |    |
| division expression |    |    |    |    |
|      quotient       |    |    |    |    |
| division expression |    |    |    |    |
|      quotient       |    |    |    |    |
| division expression |    |    |    |    |
|      quotient       |    |    |    |    |
| division expression |    |    |    |    |
|      quotient       |    |    |    |    |
| division expression |    |    |    |    |
|      quotient       |    |    |    |    |
| division expression |    |    |    |    |
|      quotient       |    |    |    |    |
| division expression |    |    |    |    |
|      quotient       |    |    |    |    |
| division expression |    |    |    |    |
|      quotient       |    |    |    |    |
Game 2
|    start number     |   |   |   |   |
|---------------------|---|---|---|---|
| division expression |   |   |   |   |
|      quotient       |   |   |   |   |
| division expression |   |   |   |   |
|      quotient       |   |   |   |   |
| division expression |   |   |   |   |
|      quotient       |   |   |   |   |
| division expression |   |   |   |   |
|      quotient       |   |   |   |   |
| division expression |   |   |   |   |
|      quotient       |   |   |   |   |
| division expression |   |   |   |   |
|      quotient       |   |   |   |   |
| division expression |   |   |   |   |
|      quotient       |   |   |   |   |
| division expression |   |   |   |   |
|      quotient       |   |   |   |   |
| division expression |   |   |   |   |
|      quotient       |   |   |   |   |
Activity Synthesis
“How was having an efficient way to divide helpful as you played Race to 1?” (I had to decide which number I was going to divide, so it was helpful to be able to do it quickly. I had to divide a few times on each turn.)
“What was a helpful strategy as you played Race to 1?” (I had to think about which number I could divide by the number I rolled. I divided the smallest number by the largest divisor to try to get to the quotient to be as small as possible so I could get to 1 first.)


aligns: no