few_shots: 
Example 1:
Concept/skill: 
Prove the addition and subtraction formulas for sine, cosine, and tangent and use them to solve problems.

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


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:
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).

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


Answer: 
No. This task does not involve an equation in two variables. There is only 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, determine whether the following problem or activity can enable students to understand the concepts or skills in the provided description.

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: Count to answer “how many?” questions about as many as 20 things arranged in a line, a rectangular array, or a circle, or as many as 10 things in a scattered configuration; given a number from 1–20, count out that many objects.
problem_activity: Narrative
The purpose of this activity is to notice the pattern that when 0 is added to a number, the number stays the same and the pattern that when 1 is added to a number, the total is the next number in the count sequence, or 1 more (MP7).
MLR2 Collect and Display.
Collect the language students use to describe what they notice about the value of the expressions when 0 and 1 are added. Display phrases such as: “When we add 0, the total is the same number that we started with, because nothing was added.” During the synthesis, invite students to borrow language from the display as needed.
Advances: Conversing, Reading
Representation: Internalize Comprehension.
Synthesis: Some students may benefit from reiterating the patterns of adding zero and adding one. Make a connection between the two patterns students should notice. For example, “When you add zero to any number you get the same number because adding zero is adding nothing”, “When you add one to any number the total is the next number in the count sequence, or one more.”
Supports accessibility for: Conceptual Processing, Organization
Launch
Groups of 2
Display student book
“Diego and Mai recorded their addition expressions and their values on this page. What do you notice? What do you wonder?” (They always added 1 or 0. Sometimes the first and last number are the same.)
30 seconds: quiet think time
1 minute: partner discussion
Share and record responses.
Activity
“Which expressions show that 0 were added?” (
\(4 + 0\)
,
\(2 + 0\)
, and
\(8 + 0\)
)
30 seconds: quiet think time
Share responses. Highlight or circle the expressions that show
\(+ 0\)
.
“When you played the game, what did you do when you had to add 0?” (Nothing. Zero means none so none were added.)
30 seconds: quiet think time
1 minute: partner discussion
Share responses.
“What do you notice about the value of the expressions when 0 are added?” (It stays the same.)
1 minute: quiet think time
1 minute: partner discussion
Share responses.
“When we add 0, the total is the same number that we started with, because nothing was added.”
Repeat the steps above with
\(+ 1\)
.
Student Facing
\(4 + 0\)
4
[IMG]
\(2 + 0\)
2
[IMG]
\(8 + 0\)
8
[IMG]
\(3 + 1\)
4
[IMG]
\(9 + 1\)
10
[IMG]
\(1 + 1\)
2
[IMG]
Student Response
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Activity Synthesis
“
\(3 + 0\)
is how many?” (
\(3 + 0\)
is 3.)
“
\(2 + 0\)
is how many?” (
\(2 + 0\)
is 2.)
“How do you know that
\(2 + 0\)
is 2?” (Because we didn’t add any more, so the 2 stayed the same.)
Repeat with
\(2 + 1\)
.


aligns: no