Let's solve the expression step by step:

The expression is:

$9 \times 12 \div 3 + 5 - 15$

1. First, perform the multiplication and division from left to right: $9 \times 12 = 108$ $108 \div 3 = 36$

2. Now, add 5: $36 + 5 = 41$

3. Finally, subtract 15: $41 - 15 = 26$

So, the result is 26.

Do you need any further details or have questions?

Here are 5 related questions to expand this:

1. What is the order of operations in solving mathematical expressions?
2. How do parentheses affect the order of operations in expressions?
3. Can you solve $8 \times 15 \div 5 + 10 - 7$?
4. How do negative numbers affect operations like subtraction?
5. What happens if we change the division in the expression to a different number?

Tip: Always remember to follow the PEMDAS rule: Parentheses, Exponents, Multiplication and Division (from left to right), Addition and Subtraction (from left to right).