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


Standard options: 
A. Prove the Pythagorean identity sin^(2)(θ) + cos^(2)(θ) = 1 and use it to find sin(θ), cos(θ),or tan(θ) given sin(θ), cos(θ), or tan(θ) and the quadrant of the angle.
B. Prove the addition and subtraction formulas for sine, cosine, and tangent and use them to solve problems.


Your response, in json format:
{
  "explanation": "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. Solving this problem does not require use of the Pythagorean identity.",
  "answer": "B"
}

Now, assign the following problem or activity to one or more relevant standards it aligns with.
shot_info: fl_problem_001894

HS
options: Given a two-digit number, mentally find 10 more or 10 less than the number, without having to count; explain the reasoning used.

Add within 100, including adding a two-digit number and a one-digit number, and adding a two-digit number and a multiple of 10, using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method and explain the reasoning used. Understand that in adding two-digit numbers, one adds tens and tens, ones and ones; and sometimes it is necessary to compose a ten.

Subtract multiples of 10 in the range 10-90 from multiples of 10 in the range 10-90 (positive or zero differences), using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method and explain the reasoning used.
problem_activity: Narrative
The purpose of this activity is for students to choose from activities focusing on two-digit numbers. Students are introduced to stage 6 of the Five in a Row center. Then students choose between that center or others previously introduced.
Students choose from any stage of previously introduced centers.
Five in a Row
Get Your Numbers in Order
Grab and Count
Required Materials
Materials to Gather
Materials from previous centers
Paper clips
Two-color counters
Materials to Copy
Five in a Row Addition and Subtraction Stage 6 Gameboard
Required Preparation
Gather materials from previous centers:
Five in a Row, Stages 1-6
Get Your Numbers in Order, Stage 1
Grab and Count, Stage 2
Launch
Groups of 2
“Now you will choose from other centers we have already learned. One of the choices is to play Five in a Row with a new gameboard. On this gameboard you will add 2 two-digit numbers that make a new ten.”
Display the center choices in the student book.
“Think about what you would like to do first.”
30 seconds: quiet think time
Activity
8 minutes: center work time
“Choose what you would like to do next.”
8 minutes: center work time
Student Facing
Choose a center.
Five in a Row
[IMG]
Get Your Numbers in Order
[IMG]
Grab and Count
[IMG]
Activity Synthesis
“What did the centers you chose help you work on?”


correct_option_index: 1