658523 divided by 21 
Let's see how many times 21 fits into 658523.

On to step 1:
If we divide 6 by 21, we get 0 and a remainder of 6.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Deduct 0 from 6 and we're left with 6.
Include the next digit (5) from the dividend after 6, then repeat: 65 / 21

Moving on to step 2:
The number 21 fits into 65 3 times, leaving a remainder of 2.
The number 3 becomes the next digit in our result. 
Result so far: 3.0
Deduct 63 from 65 and we're left with 2.
Append the next digit (8) from the dividend to 2 and continue with: 28 / 21

On to step 3:
28 divided by 21 is 1 with a remainder of 7.
Write down 1 as next digit of the result. 
Result so far: 31.0
Subtract 21 from 28 to get 7.
Bring next digit (5) of the dividend behind the 7 and repeat the process: 75 / 21

Advancing to step 4:
75 divided by 21 is 3 with a remainder of 12.
Put 3 as the next digit of the answer. 
Result so far: 313.0
Subtract 63 from 75 to get 12.
Bring next digit (2) of the dividend behind the 12 and repeat the process: 122 / 21

Step 5:
21 goes into 122 5 times with a remainder of 17.
Put 5 as the next digit of the answer. 
Result so far: 3135.0
If we take 105 away from 122, we end up with 17.
Append the next digit (3) from the dividend to 17 and continue with: 173 / 21

Moving on to step 6:
If we divide 173 by 21, we get 8 and a remainder of 5.
Put 8 as the next digit of the answer. 
Result so far: 31358.0
If we take 168 away from 173, we end up with 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 7:
If we divide 50 by 21, we get 2 and a remainder of 8.
Record the quotient 2 as the next digit in the result. 
Result so far: 31358.2
Subtracting 42 from 50 leaves us with 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 8:
80 divided by 21 is 3 with a remainder of 17.
Write down 3 as next digit of the result. 
Result so far: 31358.23
If we subtract 63 from 80, we get 17.
Since there are no more digits in the dividend, we add a zero to the remainder making it 170, and continue the process.

Advancing to step 9:
When dividing 170 by 21, we get 8 with a remainder of 2.
Write down 8 as next digit of the result. 
Result so far: 31358.238
If we take 168 away from 170, we end up 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.

Going ahead to step 10:
20 divided by 21 is 0 with a remainder of 20.
Use 0 as the next digit of our solution. 
Result so far: 31358.238
If we subtract 0 from 20, we get 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

Step 11:
21 goes into 200 9 times with a remainder of 11.
Record the quotient 9 as the next digit in the result. 
Result so far: 31358.23809
Deduct 189 from 200 and we're left 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 12:
110 divided by 21 is 5 with a remainder of 5.
The number 5 becomes the next digit in our result. 
Result so far: 31358.238095
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.

Advancing to step 13:
When dividing 50 by 21, we get 2 with a remainder of 8.
Put 2 as the next digit of the answer. 
Result so far: 31358.2380952
The remainder is 8 after subtracting 42 from 50.
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 14:
When dividing 80 by 21, we get 3 with a remainder of 17.
The next digit of our result is 3. 
Result so far: 31358.23809523
Subtracting 63 from 80 leaves us 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.

The final outcome is 31358.23809523, with a leftover of 1.7e-08.