few_shots: 
Example 1:
Concept/skill: 
Understand that by similarity, side ratios in right triangles are properties of the angles in the triangle, leading to definitions of trigonometric ratios for acute angles.

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


Answer: 
No. This problem does not directly teach how side ratios in right triangles lead to definitions of trigonometric ratios. Instead, it involves solving a trigonometric function.

Example 2:
Concept/skill: 
Solve quadratic equations in one variable.

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


Answer: 
Yes. This task shows one quadratic equation with one variable, x.

Example 3:
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.

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 $P$.


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_neg_0

HS_0

im_task_000870_pos_0

HS_1

im_task_001160_pos_0

HS_2
standard_description: Understand that the two digits of a two-digit number represent amounts of tens and ones. Understand the following as special cases:
- The numbers from 11 to 19 are composed of a ten and one, two, three, four, five, six, seven, eight, or nine ones.
- The numbers 10, 20, 30, 40, 50, 60, 70, 80, 90 refer to one, two, three, four, five, six, seven, eight, or nine tens (and 0 ones).
- 10 can be thought of as a bundle of ten ones — called a “ten.”
problem_activity: Narrative
The purpose of this activity is for students to learn stage 2 of the Check It Off center. Students take turns picking two number cards that are multiples of 10 (0–90) and choose whether to make an addition or subtraction expression. Students check off the value of the sum or difference (0–90) and then write the addition or subtraction expression on the recording sheet.
Required Materials
Materials to Gather
Connecting cubes in towers of 10 and singles
Materials to Copy
Number Cards, Multiples of 10 (0-90)
Check It Off Stage 3 Recording Sheet
Required Preparation
Create a set of cards from the blackline master for each group of 2.
Launch
Groups of 2
Give each group a set of cards, two recording sheets, and access to connecting cubes in towers of 10.
“We are going to learn a new way to do the Check It Off center. It is called Check It Off, Add or Subtract Tens.”
“Choose two cards and decide whether you want to add or subtract. After you find the sum or difference, check it off on the recording sheet and write the expression. Take turns with your partner. At the end of the game the partner who checks off the most numbers wins.”
Activity
10 minutes: partner work time
Activity Synthesis
Display a recording sheet with 90 checked off and 10 not checked off.
Display cards 40 and 50.
“Should we add or subtract these numbers? Why?” (We should subtract because
\(50 - 40 =10\)
and we haven’t checked off 10 yet, but
\(40 + 50 = 90\)
and 90 is already checked off.)


aligns: no