To solve this expression, we need to follow the order of operations (PEMDAS/BODMAS):

1. First, we calculate the exponent: 5^12 = 244,140,625.
2. Next, we multiply 244,140,625 by 231: 244,140,625 × 231 = 56,250,000,000.
3. Then, we multiply 1 by 3: 1 × 3 = 3.
4. After that, we multiply 100 by 1: 100 × 1 = 100.
5. Next, we add 0 to 100: 0 + 100 = 100.
6. Finally, we divide 108 by 3: 108 ÷ 3 = 36.

Putting it all together, the expression becomes:

3 × 56,250,000,000 × 100 + 36 = 1,687,500,000,000 + 36 = 1,687,500,000,036.