231251 ÷ 21 
Our goal is to divide 231251 by 21.

Advancing to step 1:
21 goes into 2 0 times with a remainder of 2.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtracting 0 from 2 leaves us with 2.
Grab the next digit (3) from the dividend, add it to 2, then carry on: 23 / 21

Moving on to step 2:
The number 21 fits into 23 1 times, leaving a remainder of 2.
Write down 1 as next digit of the result. 
Result so far: 1.0
The remainder is 2 after subtracting 21 from 23.
Take the next digit (1) from the dividend and append it to 2, then repeat: 21 / 21

Advancing to step 3:
21 can be fit into 21 1 times, resulting in a remainder of 0.
Write down 1 as next digit of the result. 
Result so far: 11.0
The remainder is 0 after subtracting 21 from 21.
Take the next digit (2) from the dividend and append it to 0, then repeat: 2 / 21

Moving on to step 4:
21 can be fit into 2 0 times, resulting in a remainder of 2.
Use 0 as the next digit of our solution. 
Result so far: 110.0
Deduct 0 from 2 and we're left with 2.
Append the next digit (5) from the dividend to 2 and continue with: 25 / 21

Going ahead to step 5:
When dividing 25 by 21, we get 1 with a remainder of 4.
The next digit of our result is 1. 
Result so far: 1101.0
Subtract 21 from 25 to get 4.
Bring next digit (1) of the dividend behind the 4 and repeat the process: 41 / 21

Let's proceed to step 6:
When dividing 41 by 21, we get 1 with a remainder of 20.
Put 1 as the next digit of the answer. 
Result so far: 11011.0
Subtracting 21 from 41 leaves us 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.

Going ahead to step 7:
21 can be fit into 200 9 times, resulting in a remainder of 11.
Write down 9 as next digit of the result. 
Result so far: 11011.9
Subtract 189 from 200 to get 11.
Since there are no more digits in the dividend, we add a zero to the remainder making it 110, and continue the process.

Let's proceed to step 8:
The number 21 fits into 110 5 times, leaving a remainder of 5.
Record the quotient 5 as the next digit in the result. 
Result so far: 11011.95
If we subtract 105 from 110, we get 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 9:
If we divide 50 by 21, we get 2 and a remainder of 8.
The next digit of our result is 2. 
Result so far: 11011.952
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.

Let's proceed to step 10:
The number 21 fits into 80 3 times, leaving a remainder of 17.
The number 3 becomes the next digit in our result. 
Result so far: 11011.9523
Deduct 63 from 80 and we're left with 17.
Since there are no more digits in the dividend, we add a zero to the remainder making it 170, and continue the process.

Going ahead to step 11:
170 divided by 21 is 8 with a remainder of 2.
The number 8 becomes the next digit in our result. 
Result so far: 11011.95238
Deduct 168 from 170 and we're left 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 12:
20 divided by 21 is 0 with a remainder of 20.
Put 0 as the next digit of the answer. 
Result so far: 11011.95238
Subtracting 0 from 20 leaves us 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.

Advancing to step 13:
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: 11011.9523809
Subtracting 189 from 200 leaves us 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.

Advancing to step 14:
The number 21 fits into 110 5 times, leaving a remainder of 5.
Use 5 as the next digit of our solution. 
Result so far: 11011.95238095
If we subtract 105 from 110, we get 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 outcome is 11011.95238095, with a leftover of 5e-09.