We're dividing 45712120 by 643 
Our goal is to divide 45712120 by 643.

On to step 1:
643 can be fit into 4 0 times, resulting in a remainder of 4.
The next digit of our result is 0. 
Result so far: 0.0
Subtract 0 from 4 to get 4.
Include the next digit (5) from the dividend after 4, then repeat: 45 / 643

Advancing to step 2:
The number 643 fits into 45 0 times, leaving a remainder of 45.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtract 0 from 45 to get 45.
Include the next digit (7) from the dividend after 45, then repeat: 457 / 643

Step 3:
When dividing 457 by 643, we get 0 with a remainder of 457.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
The remainder is 457 after subtracting 0 from 457.
Include the next digit (1) from the dividend after 457, then repeat: 4571 / 643

Step 4:
If we divide 4571 by 643, we get 7 and a remainder of 70.
The number 7 becomes the next digit in our result. 
Result so far: 7.0
Subtracting 4501 from 4571 leaves us with 70.
Bring next digit (2) of the dividend behind the 70 and repeat the process: 702 / 643

Moving on to step 5:
643 can be fit into 702 1 times, resulting in a remainder of 59.
Record the quotient 1 as the next digit in the result. 
Result so far: 71.0
Subtract 643 from 702 to get 59.
Bring next digit (1) of the dividend behind the 59 and repeat the process: 591 / 643

Going ahead to step 6:
If we divide 591 by 643, we get 0 and a remainder of 591.
Use 0 as the next digit of our solution. 
Result so far: 710.0
Subtract 0 from 591 to get 591.
Grab the next digit (2) from the dividend, add it to 591, then carry on: 5912 / 643

Step 7:
643 can be fit into 5912 9 times, resulting in a remainder of 125.
The number 9 becomes the next digit in our result. 
Result so far: 7109.0
If we take 5787 away from 5912, we end up with 125.
Bring next digit (0) of the dividend behind the 125 and repeat the process: 1250 / 643

Step 8:
The number 643 fits into 1250 1 times, leaving a remainder of 607.
Put 1 as the next digit of the answer. 
Result so far: 71091.0
If we subtract 643 from 1250, we get 607.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6070, and continue the process.

On to step 9:
6070 divided by 643 is 9 with a remainder of 283.
Write down 9 as next digit of the result. 
Result so far: 71091.9
Deduct 5787 from 6070 and we're left with 283.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2830, and continue the process.

Step 10:
The number 643 fits into 2830 4 times, leaving a remainder of 258.
Write down 4 as next digit of the result. 
Result so far: 71091.94
Deduct 2572 from 2830 and we're left with 258.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2580, and continue the process.

Moving on to step 11:
643 can be fit into 2580 4 times, resulting in a remainder of 8.
Record the quotient 4 as the next digit in the result. 
Result so far: 71091.944
Subtract 2572 from 2580 to get 8.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

In conclusion, the division gives 71091.944 with a balance of 0.0008.