We're dividing 258841 by 21 
We want to divide 258841 by 21.

Advancing to step 1:
If we divide 2 by 21, we get 0 and a remainder of 2.
Write down 0 as next digit of the result. 
Result so far: 0.0
If we subtract 0 from 2, we get 2.
Include the next digit (5) from the dividend after 2, then repeat: 25 / 21

On to step 2:
If we divide 25 by 21, we get 1 and a remainder of 4.
Write down 1 as next digit of the result. 
Result so far: 1.0
Subtract 21 from 25 to get 4.
Bring next digit (8) of the dividend behind the 4 and repeat the process: 48 / 21

Advancing to step 3:
If we divide 48 by 21, we get 2 and a remainder of 6.
Write down 2 as next digit of the result. 
Result so far: 12.0
If we subtract 42 from 48, we get 6.
Take the next digit (8) from the dividend and append it to 6, then repeat: 68 / 21

On to step 4:
If we divide 68 by 21, we get 3 and a remainder of 5.
The next digit of our result is 3. 
Result so far: 123.0
Subtract 63 from 68 to get 5.
Include the next digit (4) from the dividend after 5, then repeat: 54 / 21

Step 5:
The number 21 fits into 54 2 times, leaving a remainder of 12.
Record the quotient 2 as the next digit in the result. 
Result so far: 1232.0
If we take 42 away from 54, we end up with 12.
Bring next digit (1) of the dividend behind the 12 and repeat the process: 121 / 21

On to step 6:
121 divided by 21 is 5 with a remainder of 16.
The next digit of our result is 5. 
Result so far: 12325.0
Subtracting 105 from 121 leaves us 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.

On to step 7:
The number 21 fits into 160 7 times, leaving a remainder of 13.
Record the quotient 7 as the next digit in the result. 
Result so far: 12325.7
The remainder is 13 after subtracting 147 from 160.
Since there are no more digits in the dividend, we add a zero to the remainder making it 130, and continue the process.

Step 8:
If we divide 130 by 21, we get 6 and a remainder of 4.
Use 6 as the next digit of our solution. 
Result so far: 12325.76
The remainder is 4 after subtracting 126 from 130.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Step 9:
21 goes into 40 1 times with a remainder of 19.
Record the quotient 1 as the next digit in the result. 
Result so far: 12325.761
Subtracting 21 from 40 leaves us 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.

Moving on to step 10:
190 divided by 21 is 9 with a remainder of 1.
The next digit of our result is 9. 
Result so far: 12325.7619
Subtracting 189 from 190 leaves us 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.

Moving on to step 11:
21 goes into 10 0 times with a remainder of 10.
Write down 0 as next digit of the result. 
Result so far: 12325.7619
Deduct 0 from 10 and we're left with 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Let's proceed to step 12:
21 goes into 100 4 times with a remainder of 16.
The next digit of our result is 4. 
Result so far: 12325.761904
Subtracting 84 from 100 leaves us 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.

Moving on to step 13:
If we divide 160 by 21, we get 7 and a remainder of 13.
Use 7 as the next digit of our solution. 
Result so far: 12325.7619047
If we take 147 away from 160, we end up 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.

Step 14:
21 can be fit into 130 6 times, resulting in a remainder of 4.
Put 6 as the next digit of the answer. 
Result so far: 12325.76190476
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.

The final result is 12325.76190476 with a remainder of 4e-09.