12,75 х 4,03 - 9 1/2 + 6.456 / 2 + 2,6/12

Let's simplify the expression step by step.

1. First compute each part:

   • Calculate \( 12.75 \times 4.03 \)
   • Then calculate \( 9 \frac{1}{2} \)
   • Then calculate \( 6.456 \div 2 \)
   • Then calculate \( \frac{2.6}{12} \)

2. Now let's perform the calculations:

• \( 12.75 \times 4.03 = 51.4125 \)
• \( 9 \frac{1}{2} = 9.5 \)
• \( 6.456 \div 2 = 3.228 \)
• \( \frac{2.6}{12} = 0.2167 \) (approximately)

3. Now, plug these values back into the expression:

\[ 51.4125 - 9.5 + 3.228 + 0.2167 \]

4. Now perform the operations step by step:

• First, \( 51.4125 - 9.5 = 41.9125 \)
• Then, \( 41.9125 + 3.228 = 45.1405 \)
• Finally, \( 45.1405 + 0.2167 = 45.3572 \)

Thus, the final result is approximately:

\[ \boxed{45.3572} \]