12т 34кг-3456кг

To solve this equation, I will convert the value of "т" (tonnes) into kilograms.

1 tonne is equal to 1000 kilograms.

So, 12 tonnes is equal to 12 * 1000 = 12000 kilograms.

Now, we can calculate the difference between 34kg and 3456kg.

12000kg - 34kg - 3456kg = 8546kg.

Therefore, the result is 8546kg.