To create a factor tree for $211$, we first determine if $211$ can be factored further or if it is a prime number.

Step-by-step:

1. Check divisibility:

   • $211$ is odd, so it's not divisible by $2$.
   • Add the digits $2 + 1 + 1 = 4$. Since $4$ is not divisible by $3$, $211$ is not divisible by $3$.
   • It does not end in $0$ or $5$, so it's not divisible by $5$.
   • Checking divisibility by $7, 11, 13,$ and so on up to $\sqrt{211} \approx 14.5$ reveals no divisors.

2. Conclusion: $211$ is prime, meaning it cannot be factored further. The factor tree for $211$ is simply $211$ itself.

Would you like help with another number or more explanation?

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5 Questions:

1. What are prime numbers, and how do you determine if a number is prime?
2. How does divisibility by small primes help in factoring?
3. Why do we stop checking divisors at the square root of a number?
4. Can all odd numbers be prime? Why or why not?
5. What is the difference between a factor tree and prime factorization?

Tip:

To quickly determine if a number is prime, check divisibility by all primes up to its square root.