The problem states:

"Emily is thinking of a number, which she calls $n$. She finds $\frac{1}{4}$ of the number and then subtracts 3."

To express this mathematically:

1. Start by representing Emily's number as $n$.
2. To find $\frac{1}{4}$ of $n$, multiply $n$ by $\frac{1}{4}$, which gives $\frac{1}{4}n$.
3. Then subtract 3 from this expression, resulting in:

$\frac{1}{4}n - 3$

This is the correct expression that represents Emily's number after following the given steps.

Would you like more details or have any questions?

Here are 5 related questions to expand on this concept:

1. How would the expression change if she found $\frac{1}{2}$ of the number instead?
2. What would the expression look like if she subtracted 5 instead of 3?
3. If $n = 8$, what is the value of the expression $\frac{1}{4}n - 3$?
4. Can you rewrite the expression using decimal values instead of fractions?
5. How would the expression change if Emily added 3 instead of subtracting 3?

Tip: When working with fractions, remember that multiplying a number by a fraction is the same as finding a part of the number.