122151 ÷ 21 
We want to divide 122151 by 21.

Step 1:
1 divided by 21 is 0 with a remainder of 1.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Subtracting 0 from 1 leaves us with 1.
Include the next digit (2) from the dividend after 1, then repeat: 12 / 21

Advancing to step 2:
The number 21 fits into 12 0 times, leaving a remainder of 12.
The next digit of our result is 0. 
Result so far: 0.0
Deduct 0 from 12 and we're left with 12.
Bring next digit (2) of the dividend behind the 12 and repeat the process: 122 / 21

Let's proceed to step 3:
If we divide 122 by 21, we get 5 and a remainder of 17.
Put 5 as the next digit of the answer. 
Result so far: 5.0
Subtract 105 from 122 to get 17.
Fetch the next digit (1) from the dividend, attach it to 17 and continue: 171 / 21

Step 4:
The number 21 fits into 171 8 times, leaving a remainder of 3.
The number 8 becomes the next digit in our result. 
Result so far: 58.0
If we take 168 away from 171, we end up with 3.
Bring next digit (5) of the dividend behind the 3 and repeat the process: 35 / 21

Let's proceed to step 5:
21 can be fit into 35 1 times, resulting in a remainder of 14.
The next digit of our result is 1. 
Result so far: 581.0
If we subtract 21 from 35, we get 14.
Grab the next digit (1) from the dividend, add it to 14, then carry on: 141 / 21

Going ahead to step 6:
21 goes into 141 6 times with a remainder of 15.
The next digit of our result is 6. 
Result so far: 5816.0
Deduct 126 from 141 and we're left with 15.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

On to step 7:
When dividing 150 by 21, we get 7 with a remainder of 3.
The next digit of our result is 7. 
Result so far: 5816.7
If we subtract 147 from 150, we get 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 8:
21 goes into 30 1 times with a remainder of 9.
Record the quotient 1 as the next digit in the result. 
Result so far: 5816.71
Subtracting 21 from 30 leaves us with 9.
Since there are no more digits in the dividend, we add a zero to the remainder making it 90, and continue the process.

Going ahead to step 9:
21 goes into 90 4 times with a remainder of 6.
Put 4 as the next digit of the answer. 
Result so far: 5816.714
If we take 84 away from 90, we end up 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.

On to step 10:
60 divided by 21 is 2 with a remainder of 18.
Use 2 as the next digit of our solution. 
Result so far: 5816.7142
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 11:
180 divided by 21 is 8 with a remainder of 12.
Write down 8 as next digit of the result. 
Result so far: 5816.71428
The remainder is 12 after subtracting 168 from 180.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

Step 12:
21 goes into 120 5 times with a remainder of 15.
The next digit of our result is 5. 
Result so far: 5816.714285
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.

Step 13:
150 divided by 21 is 7 with a remainder of 3.
The next digit of our result is 7. 
Result so far: 5816.7142857
If we subtract 147 from 150, we get 3.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

Step 14:
30 divided by 21 is 1 with a remainder of 9.
Put 1 as the next digit of the answer. 
Result so far: 5816.71428571
If we take 21 away from 30, we end up with 9.
Since there are no more digits in the dividend, we add a zero to the remainder making it 90, and continue the process.

In conclusion, the division gives 5816.71428571 with a balance of 9e-09.