168590 ÷ 21 
We're looking to find how many times 21 goes into 168590.

Moving on to step 1:
1 divided by 21 is 0 with a remainder of 1.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we take 0 away from 1, we end up with 1.
Take the next digit (6) from the dividend and append it to 1, then repeat: 16 / 21

Step 2:
16 divided by 21 is 0 with a remainder of 16.
The next digit of our result is 0. 
Result so far: 0.0
Deduct 0 from 16 and we're left with 16.
Include the next digit (8) from the dividend after 16, then repeat: 168 / 21

On to step 3:
21 can be fit into 168 8 times, resulting in a remainder of 0.
Write down 8 as next digit of the result. 
Result so far: 8.0
If we take 168 away from 168, we end up with 0.
Include the next digit (5) from the dividend after 0, then repeat: 5 / 21

Advancing to step 4:
The number 21 fits into 5 0 times, leaving a remainder of 5.
Use 0 as the next digit of our solution. 
Result so far: 80.0
If we take 0 away from 5, we end up with 5.
Grab the next digit (9) from the dividend, add it to 5, then carry on: 59 / 21

Step 5:
21 goes into 59 2 times with a remainder of 17.
Write down 2 as next digit of the result. 
Result so far: 802.0
Subtract 42 from 59 to get 17.
Bring next digit (0) of the dividend behind the 17 and repeat the process: 170 / 21

Let's proceed to step 6:
170 divided by 21 is 8 with a remainder of 2.
The next digit of our result is 8. 
Result so far: 8028.0
The remainder is 2 after subtracting 168 from 170.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

On to step 7:
21 goes into 20 0 times with a remainder of 20.
Put 0 as the next digit of the answer. 
Result so far: 8028.0
Deduct 0 from 20 and we're left 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 8:
When dividing 200 by 21, we get 9 with a remainder of 11.
Record the quotient 9 as the next digit in the result. 
Result so far: 8028.09
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.

Step 9:
When dividing 110 by 21, we get 5 with a remainder of 5.
Write down 5 as next digit of the result. 
Result so far: 8028.095
Deduct 105 from 110 and we're left 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.

Going ahead to step 10:
50 divided by 21 is 2 with a remainder of 8.
The next digit of our result is 2. 
Result so far: 8028.0952
If we subtract 42 from 50, we 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.

On to step 11:
When dividing 80 by 21, we get 3 with a remainder of 17.
Record the quotient 3 as the next digit in the result. 
Result so far: 8028.09523
If we take 63 away from 80, we end up 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.

Moving on to step 12:
21 can be fit into 170 8 times, resulting in a remainder of 2.
Record the quotient 8 as the next digit in the result. 
Result so far: 8028.095238
Subtracting 168 from 170 leaves us 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.

Moving on to step 13:
The number 21 fits into 20 0 times, leaving a remainder of 20.
The number 0 becomes the next digit in our result. 
Result so far: 8028.095238
The remainder is 20 after subtracting 0 from 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

Moving on to step 14:
200 divided by 21 is 9 with a remainder of 11.
The number 9 becomes the next digit in our result. 
Result so far: 8028.09523809
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.

The final outcome is 8028.09523809, with a leftover of 1.1e-08.