First, solve the operations inside the parentheses:

6 + 280 = 286

Next, divide 286 by 20:

286 / 20 = 14.3

Now, multiply 810 by 40:

810 * 40 = 32,400

Then, solve the division:

32,400 / 14.3 ≈ 2,258.74

Next, multiply 10270 by 18:

10270 * 18 = 184,860

Now, divide 480 by 8:

480 / 8 = 60

Next, add 4635 and 335:

4635 + 335 = 4970

Now, multiply 60 by 4970:

60 * 4970 = 298,200

Finally, subtract the two results:

184,860 - 298,200 ≈ -113,340

So, the final answer is approximately -113,340.