We're dividing 356561 by 21 
Our goal is to divide 356561 by 21.

Step 1:
If we divide 3 by 21, we get 0 and a remainder of 3.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we subtract 0 from 3, we get 3.
Include the next digit (5) from the dividend after 3, then repeat: 35 / 21

Advancing to step 2:
35 divided by 21 is 1 with a remainder of 14.
The next digit of our result is 1. 
Result so far: 1.0
Subtract 21 from 35 to get 14.
Include the next digit (6) from the dividend after 14, then repeat: 146 / 21

Moving on to step 3:
21 goes into 146 6 times with a remainder of 20.
Use 6 as the next digit of our solution. 
Result so far: 16.0
Subtracting 126 from 146 leaves us with 20.
Take the next digit (5) from the dividend and append it to 20, then repeat: 205 / 21

Advancing to step 4:
If we divide 205 by 21, we get 9 and a remainder of 16.
Use 9 as the next digit of our solution. 
Result so far: 169.0
If we subtract 189 from 205, we get 16.
Bring next digit (6) of the dividend behind the 16 and repeat the process: 166 / 21

Advancing to step 5:
21 can be fit into 166 7 times, resulting in a remainder of 19.
Use 7 as the next digit of our solution. 
Result so far: 1697.0
Deduct 147 from 166 and we're left with 19.
Append the next digit (1) from the dividend to 19 and continue with: 191 / 21

Step 6:
When dividing 191 by 21, we get 9 with a remainder of 2.
Put 9 as the next digit of the answer. 
Result so far: 16979.0
Subtract 189 from 191 to get 2.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

Advancing to step 7:
The number 21 fits into 20 0 times, leaving a remainder of 20.
The next digit of our result is 0. 
Result so far: 16979.0
If we take 0 away from 20, we end up 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.

Step 8:
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: 16979.09
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.

Advancing to step 9:
If we divide 110 by 21, we get 5 and a remainder of 5.
The number 5 becomes the next digit in our result. 
Result so far: 16979.095
Subtract 105 from 110 to 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 10:
21 goes into 50 2 times with a remainder of 8.
The next digit of our result is 2. 
Result so far: 16979.0952
Deduct 42 from 50 and we're left 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.

Step 11:
80 divided by 21 is 3 with a remainder of 17.
Write down 3 as next digit of the result. 
Result so far: 16979.09523
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.

Let's proceed to step 12:
170 divided by 21 is 8 with a remainder of 2.
The number 8 becomes the next digit in our result. 
Result so far: 16979.095238
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.

Let's proceed to step 13:
The number 21 fits into 20 0 times, leaving a remainder of 20.
The next digit of our result is 0. 
Result so far: 16979.095238
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.

Step 14:
The number 21 fits into 200 9 times, leaving a remainder of 11.
Record the quotient 9 as the next digit in the result. 
Result so far: 16979.09523809
The remainder is 11 after subtracting 189 from 200.
Since there are no more digits in the dividend, we add a zero to the remainder making it 110, and continue the process.

The quotient of the division is 16979.09523809, and the remainder is 1.1e-08.