Let's solve the expression:

$-\frac{1}{4} - \left(-\frac{3}{5}\right)$

First, notice that subtracting a negative is the same as adding the positive of that number:

$-\frac{1}{4} + \frac{3}{5}$

Now, to add these fractions, we need a common denominator. The least common denominator (LCD) of 4 and 5 is 20. So, we rewrite each fraction with a denominator of 20:

$-\frac{1}{4} = -\frac{5}{20}$ $\frac{3}{5} = \frac{12}{20}$

Now, add the fractions:

$-\frac{5}{20} + \frac{12}{20} = \frac{12 - 5}{20} = \frac{7}{20}$

So, the final answer is:

$\frac{7}{20}$

Would you like further details or have any questions?

Here are some related questions:

1. How do you find the least common denominator (LCD) of two numbers?
2. What are the steps to simplify fractions?
3. How do you handle operations with negative numbers in fractions?
4. What is the difference between subtracting and adding fractions?
5. How can you convert an improper fraction to a mixed number?

Tip: When adding or subtracting fractions, always remember to find a common denominator to combine them correctly.