72000858 divided by 21 
We want to divide 72000858 by 21.

Moving on to step 1:
21 can be fit into 7 0 times, resulting in a remainder of 7.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
If we subtract 0 from 7, we get 7.
Bring next digit (2) of the dividend behind the 7 and repeat the process: 72 / 21

Let's proceed to step 2:
21 can be fit into 72 3 times, resulting in a remainder of 9.
Write down 3 as next digit of the result. 
Result so far: 3.0
Subtracting 63 from 72 leaves us with 9.
Append the next digit (0) from the dividend to 9 and continue with: 90 / 21

Going ahead to step 3:
21 can be fit into 90 4 times, resulting in a remainder of 6.
Record the quotient 4 as the next digit in the result. 
Result so far: 34.0
If we take 84 away from 90, we end up with 6.
Append the next digit (0) from the dividend to 6 and continue with: 60 / 21

Going ahead to step 4:
The number 21 fits into 60 2 times, leaving a remainder of 18.
The number 2 becomes the next digit in our result. 
Result so far: 342.0
Subtract 42 from 60 to get 18.
Grab the next digit (0) from the dividend, add it to 18, then carry on: 180 / 21

On to step 5:
21 can be fit into 180 8 times, resulting in a remainder of 12.
Put 8 as the next digit of the answer. 
Result so far: 3428.0
If we subtract 168 from 180, we get 12.
Grab the next digit (8) from the dividend, add it to 12, then carry on: 128 / 21

Moving on to step 6:
If we divide 128 by 21, we get 6 and a remainder of 2.
Write down 6 as next digit of the result. 
Result so far: 34286.0
Deduct 126 from 128 and we're left with 2.
Grab the next digit (5) from the dividend, add it to 2, then carry on: 25 / 21

Let's proceed to step 7:
If we divide 25 by 21, we get 1 and a remainder of 4.
Use 1 as the next digit of our solution. 
Result so far: 342861.0
Deduct 21 from 25 and we're left with 4.
Take the next digit (8) from the dividend and append it to 4, then repeat: 48 / 21

Moving on to step 8:
48 divided by 21 is 2 with a remainder of 6.
The next digit of our result is 2. 
Result so far: 3428612.0
Subtract 42 from 48 to get 6.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

Let's proceed to step 9:
If we divide 60 by 21, we get 2 and a remainder of 18.
The next digit of our result is 2. 
Result so far: 3428612.2
Subtracting 42 from 60 leaves us with 18.
Since there are no more digits in the dividend, we add a zero to the remainder making it 180, and continue the process.

Going ahead to step 10:
21 goes into 180 8 times with a remainder of 12.
Use 8 as the next digit of our solution. 
Result so far: 3428612.28
Deduct 168 from 180 and we're left with 12.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

Moving on to step 11:
21 can be fit into 120 5 times, resulting in a remainder of 15.
Record the quotient 5 as the next digit in the result. 
Result so far: 3428612.285
If we subtract 105 from 120, we get 15.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

Let's proceed to step 12:
21 can be fit into 150 7 times, resulting in a remainder of 3.
Put 7 as the next digit of the answer. 
Result so far: 3428612.2857
If we take 147 away from 150, we end up with 3.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

Going ahead to step 13:
21 can be fit into 30 1 times, resulting in a remainder of 9.
The next digit of our result is 1. 
Result so far: 3428612.28571
Subtract 21 from 30 to get 9.
Since there are no more digits in the dividend, we add a zero to the remainder making it 90, and continue the process.

On to step 14:
When dividing 90 by 21, we get 4 with a remainder of 6.
The next digit of our result is 4. 
Result so far: 3428612.285714
Deduct 84 from 90 and we're left with 6.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

Moving on to step 15:
If we divide 60 by 21, we get 2 and a remainder of 18.
Record the quotient 2 as the next digit in the result. 
Result so far: 3428612.2857142
If we subtract 42 from 60, we get 18.
Since there are no more digits in the dividend, we add a zero to the remainder making it 180, and continue the process.

Moving on to step 16:
180 divided by 21 is 8 with a remainder of 12.
The number 8 becomes the next digit in our result. 
Result so far: 3428612.28571428
If we subtract 168 from 180, we get 12.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

The final outcome is 3428612.28571428, with a leftover of 1.2e-08.