Here are the solutions to the mathematical expressions shown in the image:

1. $9 \cdot (38 - 30)$
   $38 - 30 = 8$
   $9 \cdot 8 = 72$

2. $65 - (49 - 19)$
   $49 - 19 = 30$
   $65 - 30 = 35$

3. $28 + 45 \div 5$
   $45 \div 5 = 9$
   $28 + 9 = 37$

4. $8 \cdot 7 + 5 \cdot 6$
   $8 \cdot 7 = 56$, $5 \cdot 6 = 30$
   $56 + 30 = 86$

5. $9 \cdot 9 - 28 \div 7$
   $9 \cdot 9 = 81$, $28 \div 7 = 4$
   $81 - 4 = 77$

6. $63 \div 7 + 54 \div 6$
   $63 \div 7 = 9$, $54 \div 6 = 9$
   $9 + 9 = 18$

7. $7 \cdot (100 - 91)$
   $100 - 91 = 9$
   $7 \cdot 9 = 63$

8. $6 \cdot (75 - 65)$
   $75 - 65 = 10$
   $6 \cdot 10 = 60$

9. $7 + 36 \div 4$
   $36 \div 4 = 9$
   $7 + 9 = 16$

Would you like further clarification or details about these calculations?

Related Questions:

1. How do we prioritize operations in multi-step expressions (e.g., BODMAS/PEMDAS)?
2. How do parentheses affect the outcome of a mathematical expression?
3. Can you explain how to handle division and multiplication when they appear together?
4. Why is it important to simplify parts of expressions step by step?
5. What are some common mistakes when solving expressions like these?

Tip:

Always follow the order of operations (BODMAS/PEMDAS) to ensure the correct result!