We're dividing 66566778 by 643 
Let's see how many times 643 fits into 66566778.

Let's proceed to step 1:
6 divided by 643 is 0 with a remainder of 6.
Write down 0 as next digit of the result. 
Result so far: 0.0
If we take 0 away from 6, we end up with 6.
Append the next digit (6) from the dividend to 6 and continue with: 66 / 643

Moving on to step 2:
When dividing 66 by 643, we get 0 with a remainder of 66.
Put 0 as the next digit of the answer. 
Result so far: 0.0
The remainder is 66 after subtracting 0 from 66.
Grab the next digit (5) from the dividend, add it to 66, then carry on: 665 / 643

Going ahead to step 3:
643 goes into 665 1 times with a remainder of 22.
Record the quotient 1 as the next digit in the result. 
Result so far: 1.0
The remainder is 22 after subtracting 643 from 665.
Grab the next digit (6) from the dividend, add it to 22, then carry on: 226 / 643

On to step 4:
226 divided by 643 is 0 with a remainder of 226.
The next digit of our result is 0. 
Result so far: 10.0
If we take 0 away from 226, we end up with 226.
Fetch the next digit (6) from the dividend, attach it to 226 and continue: 2266 / 643

Moving on to step 5:
When dividing 2266 by 643, we get 3 with a remainder of 337.
The next digit of our result is 3. 
Result so far: 103.0
Deduct 1929 from 2266 and we're left with 337.
Fetch the next digit (7) from the dividend, attach it to 337 and continue: 3377 / 643

Moving on to step 6:
3377 divided by 643 is 5 with a remainder of 162.
Write down 5 as next digit of the result. 
Result so far: 1035.0
If we take 3215 away from 3377, we end up with 162.
Bring next digit (7) of the dividend behind the 162 and repeat the process: 1627 / 643

Going ahead to step 7:
If we divide 1627 by 643, we get 2 and a remainder of 341.
Write down 2 as next digit of the result. 
Result so far: 10352.0
If we subtract 1286 from 1627, we get 341.
Grab the next digit (8) from the dividend, add it to 341, then carry on: 3418 / 643

Moving on to step 8:
643 goes into 3418 5 times with a remainder of 203.
The next digit of our result is 5. 
Result so far: 103525.0
Deduct 3215 from 3418 and we're left with 203.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2030, and continue the process.

Going ahead to step 9:
643 goes into 2030 3 times with a remainder of 101.
The number 3 becomes the next digit in our result. 
Result so far: 103525.3
The remainder is 101 after subtracting 1929 from 2030.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1010, and continue the process.

Going ahead to step 10:
When dividing 1010 by 643, we get 1 with a remainder of 367.
Record the quotient 1 as the next digit in the result. 
Result so far: 103525.31
Deduct 643 from 1010 and we're left with 367.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3670, and continue the process.

Moving on to step 11:
The number 643 fits into 3670 5 times, leaving a remainder of 455.
Record the quotient 5 as the next digit in the result. 
Result so far: 103525.315
Subtract 3215 from 3670 to get 455.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4550, and continue the process.

Moving on to step 12:
643 can be fit into 4550 7 times, resulting in a remainder of 49.
The number 7 becomes the next digit in our result. 
Result so far: 103525.3157
Subtract 4501 from 4550 to get 49.
Since there are no more digits in the dividend, we add a zero to the remainder making it 490, and continue the process.

On to step 13:
643 goes into 490 0 times with a remainder of 490.
Use 0 as the next digit of our solution. 
Result so far: 103525.3157
Subtracting 0 from 490 leaves us with 490.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4900, and continue the process.

Going ahead to step 14:
The number 643 fits into 4900 7 times, leaving a remainder of 399.
The number 7 becomes the next digit in our result. 
Result so far: 103525.315707
Deduct 4501 from 4900 and we're left with 399.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3990, and continue the process.

Moving on to step 15:
3990 divided by 643 is 6 with a remainder of 132.
Write down 6 as next digit of the result. 
Result so far: 103525.3157076
Deduct 3858 from 3990 and we're left with 132.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1320, and continue the process.

On to step 16:
If we divide 1320 by 643, we get 2 and a remainder of 34.
Use 2 as the next digit of our solution. 
Result so far: 103525.31570762
Deduct 1286 from 1320 and we're left with 34.
Since there are no more digits in the dividend, we add a zero to the remainder making it 340, and continue the process.

The final result is 103525.31570762 with a remainder of 3.4e-08.