We look at the division of 18430631 by 643 
Let's see how many times 643 fits into 18430631.

Let's proceed to step 1:
If we divide 1 by 643, we get 0 and a remainder of 1.
The next digit of our result is 0. 
Result so far: 0.0
The remainder is 1 after subtracting 0 from 1.
Grab the next digit (8) from the dividend, add it to 1, then carry on: 18 / 643

Advancing to step 2:
643 goes into 18 0 times with a remainder of 18.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we subtract 0 from 18, we get 18.
Take the next digit (4) from the dividend and append it to 18, then repeat: 184 / 643

Going ahead to step 3:
643 goes into 184 0 times with a remainder of 184.
Write down 0 as next digit of the result. 
Result so far: 0.0
Subtract 0 from 184 to get 184.
Include the next digit (3) from the dividend after 184, then repeat: 1843 / 643

Let's proceed to step 4:
If we divide 1843 by 643, we get 2 and a remainder of 557.
Write down 2 as next digit of the result. 
Result so far: 2.0
Subtract 1286 from 1843 to get 557.
Bring next digit (0) of the dividend behind the 557 and repeat the process: 5570 / 643

Going ahead to step 5:
643 can be fit into 5570 8 times, resulting in a remainder of 426.
The next digit of our result is 8. 
Result so far: 28.0
Subtract 5144 from 5570 to get 426.
Append the next digit (6) from the dividend to 426 and continue with: 4266 / 643

Going ahead to step 6:
The number 643 fits into 4266 6 times, leaving a remainder of 408.
The number 6 becomes the next digit in our result. 
Result so far: 286.0
If we take 3858 away from 4266, we end up with 408.
Take the next digit (3) from the dividend and append it to 408, then repeat: 4083 / 643

Step 7:
If we divide 4083 by 643, we get 6 and a remainder of 225.
Write down 6 as next digit of the result. 
Result so far: 2866.0
Subtract 3858 from 4083 to get 225.
Bring next digit (1) of the dividend behind the 225 and repeat the process: 2251 / 643

Advancing to step 8:
If we divide 2251 by 643, we get 3 and a remainder of 322.
Put 3 as the next digit of the answer. 
Result so far: 28663.0
Subtract 1929 from 2251 to get 322.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3220, and continue the process.

Let's proceed to step 9:
The number 643 fits into 3220 5 times, leaving a remainder of 5.
Put 5 as the next digit of the answer. 
Result so far: 28663.5
Deduct 3215 from 3220 and we're left with 5.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

Step 10:
When dividing 50 by 643, we get 0 with a remainder of 50.
Put 0 as the next digit of the answer. 
Result so far: 28663.5
If we subtract 0 from 50, we get 50.
Since there are no more digits in the dividend, we add a zero to the remainder making it 500, and continue the process.

Moving on to step 11:
643 goes into 500 0 times with a remainder of 500.
The number 0 becomes the next digit in our result. 
Result so far: 28663.5
If we subtract 0 from 500, we get 500.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5000, and continue the process.

In conclusion, the division gives 28663.5 with a balance of 0.05.