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


Mathematical concept/skill options: 
A. Prove and apply trigonometric identities.
B. Model periodic phenomena with trigonometric functions.
C. Interpret functions that arise in applications in terms of the context.
D. Build a function that models a relationship between two quantities.
E. Define, evaluate, and compare functions.
F. Use functions to model relationships between quantities.
G. Understand the concept of a function and use function notation.
H. Analyze functions using different representations.
I. Extend the domain of trigonometric functions using the unit circle.
J. Interpret expressions for functions in terms of the situation they model.
K. Build new functions from existing functions.
L. Construct and compare linear and exponential models and solve problems.


Your response:
Thought: This problem applies trigonometric identities, including the angle addition formula for cosine.
Answer: A

Now, assign the following problem or activity to one or more relevant mathematical concepts/skills it teaches.
shot_info: fl_problem_001894

HS
options: Use place value understanding and properties of operations to add and subtract.

Understand place value.

Use place value understanding and properties of operations to perform multi-digit arithmetic. (A range of algorithms may be used.)

Work with numbers 11–19 to gain foundations for place value.

Generalize place value understanding for multi-digit whole numbers.
Grade 4 expectations in this domain are limited to whole numbers less than or equal to 1,000,000.

Use place value understanding and properties of operations to perform multi-digit arithmetic.
Grade 4 expectations in this domain are limited to whole numbers less than or equal to 1,000,000.

Understand the place value system.

Perform operations with multi-digit whole numbers and with decimals to hundredths.

Extend the counting sequence.
problem_activity: Narrative
The purpose of this activity is for students to apply what they learned about rounding in prior lessons to think about all the numbers that would round to a given number. Students should be encouraged to use whatever representations make sense to them. Although the number line is often used to represent rounding, it is also worth sharing other ways that students are representing or thinking about rounding.
MLR8 Discussion Supports.
Synthesis: Some students may benefit from the opportunity to rehearse what they will say with a partner before they share with the whole class.
Advances: Speaking
Launch
Groups of 2
“Diego is thinking of a number. When you round Diego's number to the nearest ten, the answer is 40. What's a number that could be Diego's number? What's a number that could not be Diego's number?” (38 rounds to 40 so it could be his number. 34 does not round to 40 so it couldn't be his number.)
30 seconds: quiet think time
Share 3–5 responses. Highlight the idea that more than one number can round to 40 and that some numbers are greater than 40 and some are less than 40.
Activity
“Work with your partner on all these problems. Be sure to justify your reasoning.”
5–7 minutes: partner work time
Student Facing
What are all the numbers that would round to 50 if you're rounding to the nearest ten? You can use this number line if it helps you.
[IMG]
What are all the numbers that would round to 70 if you're rounding to the nearest ten?
What are all the numbers that would round to 600 if you're rounding to the nearest hundred?
If you finish early, find the numbers that would round to 100 and to 500 if you’re rounding to the nearest hundred. Compare your lists with a partner's lists and discuss patterns you see.
Student Response
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Advancing Student Thinking
If students don’t find all the numbers that round to the given number, consider asking:
“How did you determine that these numbers would round to ____?”
“How could you use a number line to find all the numbers that round to ___?”
Activity Synthesis
“How did you decide what numbers would round to 40?” (We looked at all the numbers that are closer to 40 than 50 or 30.)
Consider asking:
“What does 35 round to?” (40 because it is halfway between 30 and 40)
“What does 45 round to?” (50 because it is halfway between 40 and 50)
“Look at your responses for the first 2 problems. What patterns do you see in the numbers? Why is that happening?” (I see they each start with a 5 in the ones place below it because it’s halfway to the nearest ten, and the numbers end with a 4 in the ones place because that is closer than the next ten.)
“How did you use what you learned from the first 2 problems to think about the last problem?” (Instead of thinking about fives, we thought about fifties. We looked at all the numbers that are closer to 600 than 500 or 700.)
Consider asking:
“What does 550 round to?” (600 because it is halfway between 500 and 600.)
“What does 650 round to?” (700 because it is halfway between 600 and 700.)


correct_option_index: 2