We look at the division of 623158 by 21 
Let's see how many times 21 fits into 623158.

Moving on to step 1:
When dividing 6 by 21, we get 0 with a remainder of 6.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtracting 0 from 6 leaves us with 6.
Include the next digit (2) from the dividend after 6, then repeat: 62 / 21

On to step 2:
21 can be fit into 62 2 times, resulting in a remainder of 20.
Use 2 as the next digit of our solution. 
Result so far: 2.0
If we subtract 42 from 62, we get 20.
Grab the next digit (3) from the dividend, add it to 20, then carry on: 203 / 21

Going ahead to step 3:
21 goes into 203 9 times with a remainder of 14.
Write down 9 as next digit of the result. 
Result so far: 29.0
Deduct 189 from 203 and we're left with 14.
Append the next digit (1) from the dividend to 14 and continue with: 141 / 21

Moving on to step 4:
If we divide 141 by 21, we get 6 and a remainder of 15.
The number 6 becomes the next digit in our result. 
Result so far: 296.0
Subtracting 126 from 141 leaves us with 15.
Append the next digit (5) from the dividend to 15 and continue with: 155 / 21

On to step 5:
The number 21 fits into 155 7 times, leaving a remainder of 8.
Write down 7 as next digit of the result. 
Result so far: 2967.0
If we subtract 147 from 155, we get 8.
Fetch the next digit (8) from the dividend, attach it to 8 and continue: 88 / 21

On to step 6:
21 can be fit into 88 4 times, resulting in a remainder of 4.
The number 4 becomes the next digit in our result. 
Result so far: 29674.0
Subtract 84 from 88 to get 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

On to step 7:
21 can be fit into 40 1 times, resulting in a remainder of 19.
Use 1 as the next digit of our solution. 
Result so far: 29674.1
Deduct 21 from 40 and we're left with 19.
Since there are no more digits in the dividend, we add a zero to the remainder making it 190, and continue the process.

Going ahead to step 8:
When dividing 190 by 21, we get 9 with a remainder of 1.
Write down 9 as next digit of the result. 
Result so far: 29674.19
The remainder is 1 after subtracting 189 from 190.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Moving on to step 9:
10 divided by 21 is 0 with a remainder of 10.
Put 0 as the next digit of the answer. 
Result so far: 29674.19
If we subtract 0 from 10, we get 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Advancing to step 10:
21 can be fit into 100 4 times, resulting in a remainder of 16.
The number 4 becomes the next digit in our result. 
Result so far: 29674.1904
If we take 84 away from 100, we end up with 16.
Since there are no more digits in the dividend, we add a zero to the remainder making it 160, and continue the process.

Let's proceed to step 11:
160 divided by 21 is 7 with a remainder of 13.
Use 7 as the next digit of our solution. 
Result so far: 29674.19047
Deduct 147 from 160 and we're left with 13.
Since there are no more digits in the dividend, we add a zero to the remainder making it 130, and continue the process.

On to step 12:
When dividing 130 by 21, we get 6 with a remainder of 4.
Write down 6 as next digit of the result. 
Result so far: 29674.190476
Deduct 126 from 130 and we're left with 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Going ahead to step 13:
If we divide 40 by 21, we get 1 and a remainder of 19.
Put 1 as the next digit of the answer. 
Result so far: 29674.1904761
If we subtract 21 from 40, we get 19.
Since there are no more digits in the dividend, we add a zero to the remainder making it 190, and continue the process.

Moving on to step 14:
The number 21 fits into 190 9 times, leaving a remainder of 1.
The number 9 becomes the next digit in our result. 
Result so far: 29674.19047619
Deduct 189 from 190 and we're left with 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Our division results in 29674.19047619 with a remaining 1e-09.