We look at the division of 570790 by 21 
We want to figure out the number of times 570790 can be divided by 21.

Going ahead to step 1:
21 goes into 5 0 times with a remainder of 5.
Write down 0 as next digit of the result. 
Result so far: 0.0
If we subtract 0 from 5, we get 5.
Take the next digit (7) from the dividend and append it to 5, then repeat: 57 / 21

Advancing to step 2:
The number 21 fits into 57 2 times, leaving a remainder of 15.
Put 2 as the next digit of the answer. 
Result so far: 2.0
Deduct 42 from 57 and we're left with 15.
Take the next digit (0) from the dividend and append it to 15, then repeat: 150 / 21

Advancing to step 3:
The number 21 fits into 150 7 times, leaving a remainder of 3.
Write down 7 as next digit of the result. 
Result so far: 27.0
Subtract 147 from 150 to get 3.
Take the next digit (7) from the dividend and append it to 3, then repeat: 37 / 21

Advancing to step 4:
If we divide 37 by 21, we get 1 and a remainder of 16.
Record the quotient 1 as the next digit in the result. 
Result so far: 271.0
If we take 21 away from 37, we end up with 16.
Grab the next digit (9) from the dividend, add it to 16, then carry on: 169 / 21

Let's proceed to step 5:
The number 21 fits into 169 8 times, leaving a remainder of 1.
Record the quotient 8 as the next digit in the result. 
Result so far: 2718.0
Subtract 168 from 169 to get 1.
Grab the next digit (0) from the dividend, add it to 1, then carry on: 10 / 21

On to step 6:
21 goes into 10 0 times with a remainder of 10.
Write down 0 as next digit of the result. 
Result so far: 27180.0
The remainder is 10 after subtracting 0 from 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Advancing to step 7:
If we divide 100 by 21, we get 4 and a remainder of 16.
Put 4 as the next digit of the answer. 
Result so far: 27180.4
If we take 84 away from 100, we end up 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.

Let's proceed to step 8:
The number 21 fits into 160 7 times, leaving a remainder of 13.
Put 7 as the next digit of the answer. 
Result so far: 27180.47
Deduct 147 from 160 and we're left 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.

On to step 9:
21 goes into 130 6 times with a remainder of 4.
Write down 6 as next digit of the result. 
Result so far: 27180.476
Subtracting 126 from 130 leaves us 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.

Moving on to step 10:
21 can be fit into 40 1 times, resulting in a remainder of 19.
The next digit of our result is 1. 
Result so far: 27180.4761
Subtract 21 from 40 to get 19.
Since there are no more digits in the dividend, we add a zero to the remainder making it 190, and continue the process.

Step 11:
If we divide 190 by 21, we get 9 and a remainder of 1.
Use 9 as the next digit of our solution. 
Result so far: 27180.47619
Deduct 189 from 190 and we're left 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.

Let's proceed to step 12:
21 can be fit into 10 0 times, resulting in a remainder of 10.
The next digit of our result is 0. 
Result so far: 27180.47619
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.

On to step 13:
21 can be fit into 100 4 times, resulting in a remainder of 16.
Use 4 as the next digit of our solution. 
Result so far: 27180.4761904
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.

Advancing to step 14:
160 divided by 21 is 7 with a remainder of 13.
Use 7 as the next digit of our solution. 
Result so far: 27180.47619047
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.

The final outcome is 27180.47619047, with a leftover of 1.3e-08.