81287681 divided by 21 
We want to divide 81287681 by 21.

Moving on to step 1:
The number 21 fits into 8 0 times, leaving a remainder of 8.
The next digit of our result is 0. 
Result so far: 0.0
If we subtract 0 from 8, we get 8.
Include the next digit (1) from the dividend after 8, then repeat: 81 / 21

On to step 2:
21 can be fit into 81 3 times, resulting in a remainder of 18.
Record the quotient 3 as the next digit in the result. 
Result so far: 3.0
If we take 63 away from 81, we end up with 18.
Grab the next digit (2) from the dividend, add it to 18, then carry on: 182 / 21

Moving on to step 3:
182 divided by 21 is 8 with a remainder of 14.
Put 8 as the next digit of the answer. 
Result so far: 38.0
Deduct 168 from 182 and we're left with 14.
Take the next digit (8) from the dividend and append it to 14, then repeat: 148 / 21

Moving on to step 4:
If we divide 148 by 21, we get 7 and a remainder of 1.
Record the quotient 7 as the next digit in the result. 
Result so far: 387.0
If we subtract 147 from 148, we get 1.
Take the next digit (7) from the dividend and append it to 1, then repeat: 17 / 21

Moving on to step 5:
21 goes into 17 0 times with a remainder of 17.
The number 0 becomes the next digit in our result. 
Result so far: 3870.0
Subtract 0 from 17 to get 17.
Grab the next digit (6) from the dividend, add it to 17, then carry on: 176 / 21

Advancing to step 6:
21 goes into 176 8 times with a remainder of 8.
Use 8 as the next digit of our solution. 
Result so far: 38708.0
Subtract 168 from 176 to get 8.
Include the next digit (8) from the dividend after 8, then repeat: 88 / 21

Step 7:
If we divide 88 by 21, we get 4 and a remainder of 4.
The number 4 becomes the next digit in our result. 
Result so far: 387084.0
If we take 84 away from 88, we end up with 4.
Grab the next digit (1) from the dividend, add it to 4, then carry on: 41 / 21

Step 8:
21 goes into 41 1 times with a remainder of 20.
Put 1 as the next digit of the answer. 
Result so far: 3870841.0
Deduct 21 from 41 and we're left with 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

Moving on to step 9:
If we divide 200 by 21, we get 9 and a remainder of 11.
Record the quotient 9 as the next digit in the result. 
Result so far: 3870841.9
If we take 189 away from 200, we end up with 11.
Since there are no more digits in the dividend, we add a zero to the remainder making it 110, and continue the process.

Going ahead to step 10:
21 goes into 110 5 times with a remainder of 5.
The next digit of our result is 5. 
Result so far: 3870841.95
If we take 105 away from 110, we end up 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.

Moving on to step 11:
When dividing 50 by 21, we get 2 with a remainder of 8.
The number 2 becomes the next digit in our result. 
Result so far: 3870841.952
Subtract 42 from 50 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.

On to step 12:
21 goes into 80 3 times with a remainder of 17.
The number 3 becomes the next digit in our result. 
Result so far: 3870841.9523
Subtract 63 from 80 to get 17.
Since there are no more digits in the dividend, we add a zero to the remainder making it 170, and continue the process.

Step 13:
The number 21 fits into 170 8 times, leaving a remainder of 2.
Write down 8 as next digit of the result. 
Result so far: 3870841.95238
If we take 168 away from 170, we end up with 2.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

Let's proceed to step 14:
21 goes into 20 0 times with a remainder of 20.
Record the quotient 0 as the next digit in the result. 
Result so far: 3870841.95238
The remainder is 20 after subtracting 0 from 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

Advancing to step 15:
200 divided by 21 is 9 with a remainder of 11.
Write down 9 as next digit of the result. 
Result so far: 3870841.9523809
Deduct 189 from 200 and we're left with 11.
Since there are no more digits in the dividend, we add a zero to the remainder making it 110, and continue the process.

Step 16:
21 can be fit into 110 5 times, resulting in a remainder of 5.
Write down 5 as next digit of the result. 
Result so far: 3870841.95238095
Deduct 105 from 110 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.

The final result is 3870841.95238095 with a remainder of 5e-09.