Let's analyze each of the expressions from the image to determine whether the result is positive.

1. $0.25 + (-0.75)$
   $0.25 - 0.75 = -0.50$ (This is negative).

2. $\frac{5}{7} + \left(-\frac{5}{7}\right)$
   $\frac{5}{7} - \frac{5}{7} = 0$ (This is zero, not positive).

3. $-1\frac{1}{5} + 1\frac{4}{5}$
   Convert to improper fractions:
   $-1\frac{1}{5} = -\frac{6}{5},\ \ 1\frac{4}{5} = \frac{9}{5}$.
   $-\frac{6}{5} + \frac{9}{5} = \frac{3}{5}$ (This is positive).

4. $-4.25 + 4.75$
   $-4.25 + 4.75 = 0.50$ (This is positive).

5. $8\frac{1}{3} + \left(-7\frac{1}{5}\right)$
   Convert to improper fractions:
   $8\frac{1}{3} = \frac{25}{3},\ \ 7\frac{1}{5} = \frac{36}{5}$.
   Find the least common denominator (LCD = 15):
   $\frac{25}{3} = \frac{125}{15},\ \ \frac{36}{5} = \frac{108}{15}$.
   $\frac{125}{15} - \frac{108}{15} = \frac{17}{15}$ (This is positive).

6. $\frac{8}{3} - \frac{8}{7}$
   Find the least common denominator (LCD = 21):
   $\frac{8}{3} = \frac{56}{21},\ \ \frac{8}{7} = \frac{24}{21}$.
   $\frac{56}{21} - \frac{24}{21} = \frac{32}{21}$ (This is positive).

Conclusion:

The expressions that result in positive numbers are:

• Expression 3: $-1\frac{1}{5} + 1\frac{4}{5}$
• Expression 4: $-4.25 + 4.75$
• Expression 5: $8\frac{1}{3} + \left(-7\frac{1}{5}\right)$
• Expression 6: $\frac{8}{3} - \frac{8}{7}$

Do you want any further clarification on these?

Here are 5 related questions you might explore:

1. How do you convert mixed numbers into improper fractions?
2. What is the least common denominator, and how do you calculate it?
3. How do you simplify fractions after addition or subtraction?
4. What are the rules for adding and subtracting fractions with unlike denominators?
5. How does adding a negative number affect the overall result?

Tip: When dealing with fractions, always convert mixed numbers to improper fractions for easier calculation.