81458786 ÷ 642 
Let's see how many times 642 fits into 81458786.

Going ahead to step 1:
If we divide 8 by 642, we get 0 and a remainder of 8.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Subtract 0 from 8 to get 8.
Append the next digit (1) from the dividend to 8 and continue with: 81 / 642

Step 2:
642 can be fit into 81 0 times, resulting in a remainder of 81.
Put 0 as the next digit of the answer. 
Result so far: 0.0
The remainder is 81 after subtracting 0 from 81.
Include the next digit (4) from the dividend after 81, then repeat: 814 / 642

Going ahead to step 3:
The number 642 fits into 814 1 times, leaving a remainder of 172.
Record the quotient 1 as the next digit in the result. 
Result so far: 1.0
Subtract 642 from 814 to get 172.
Append the next digit (5) from the dividend to 172 and continue with: 1725 / 642

Going ahead to step 4:
If we divide 1725 by 642, we get 2 and a remainder of 441.
Record the quotient 2 as the next digit in the result. 
Result so far: 12.0
The remainder is 441 after subtracting 1284 from 1725.
Grab the next digit (8) from the dividend, add it to 441, then carry on: 4418 / 642

Let's proceed to step 5:
642 can be fit into 4418 6 times, resulting in a remainder of 566.
Put 6 as the next digit of the answer. 
Result so far: 126.0
Subtracting 3852 from 4418 leaves us with 566.
Fetch the next digit (7) from the dividend, attach it to 566 and continue: 5667 / 642

Moving on to step 6:
642 goes into 5667 8 times with a remainder of 531.
The number 8 becomes the next digit in our result. 
Result so far: 1268.0
Deduct 5136 from 5667 and we're left with 531.
Include the next digit (8) from the dividend after 531, then repeat: 5318 / 642

Let's proceed to step 7:
5318 divided by 642 is 8 with a remainder of 182.
The next digit of our result is 8. 
Result so far: 12688.0
If we subtract 5136 from 5318, we get 182.
Include the next digit (6) from the dividend after 182, then repeat: 1826 / 642

Going ahead to step 8:
642 can be fit into 1826 2 times, resulting in a remainder of 542.
The next digit of our result is 2. 
Result so far: 126882.0
If we take 1284 away from 1826, we end up with 542.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5420, and continue the process.

Going ahead to step 9:
5420 divided by 642 is 8 with a remainder of 284.
The next digit of our result is 8. 
Result so far: 126882.8
If we take 5136 away from 5420, we end up with 284.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2840, and continue the process.

Going ahead to step 10:
2840 divided by 642 is 4 with a remainder of 272.
Put 4 as the next digit of the answer. 
Result so far: 126882.84
The remainder is 272 after subtracting 2568 from 2840.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2720, and continue the process.

On to step 11:
If we divide 2720 by 642, we get 4 and a remainder of 152.
Write down 4 as next digit of the result. 
Result so far: 126882.844
If we take 2568 away from 2720, we end up with 152.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1520, and continue the process.

The final result is 126882.844 with a remainder of 0.0152.