We look at the division of 666342 by 21 
Let's see how many times 21 fits into 666342.

Moving on to step 1:
21 can be fit into 6 0 times, resulting in a remainder of 6.
The next digit of our result is 0. 
Result so far: 0.0
The remainder is 6 after subtracting 0 from 6.
Include the next digit (6) from the dividend after 6, then repeat: 66 / 21

Advancing to step 2:
The number 21 fits into 66 3 times, leaving a remainder of 3.
Put 3 as the next digit of the answer. 
Result so far: 3.0
Deduct 63 from 66 and we're left with 3.
Grab the next digit (6) from the dividend, add it to 3, then carry on: 36 / 21

On to step 3:
21 goes into 36 1 times with a remainder of 15.
Put 1 as the next digit of the answer. 
Result so far: 31.0
If we take 21 away from 36, we end up with 15.
Fetch the next digit (3) from the dividend, attach it to 15 and continue: 153 / 21

Step 4:
When dividing 153 by 21, we get 7 with a remainder of 6.
Write down 7 as next digit of the result. 
Result so far: 317.0
The remainder is 6 after subtracting 147 from 153.
Append the next digit (4) from the dividend to 6 and continue with: 64 / 21

Going ahead to step 5:
The number 21 fits into 64 3 times, leaving a remainder of 1.
The number 3 becomes the next digit in our result. 
Result so far: 3173.0
Subtract 63 from 64 to get 1.
Append the next digit (2) from the dividend to 1 and continue with: 12 / 21

Going ahead to step 6:
21 goes into 12 0 times with a remainder of 12.
Use 0 as the next digit of our solution. 
Result so far: 31730.0
Deduct 0 from 12 and we're left with 12.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

Step 7:
120 divided by 21 is 5 with a remainder of 15.
The number 5 becomes the next digit in our result. 
Result so far: 31730.5
If we subtract 105 from 120, we get 15.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

Advancing to step 8:
The number 21 fits into 150 7 times, leaving a remainder of 3.
Use 7 as the next digit of our solution. 
Result so far: 31730.57
The remainder is 3 after subtracting 147 from 150.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

Going ahead to step 9:
21 goes into 30 1 times with a remainder of 9.
Use 1 as the next digit of our solution. 
Result so far: 31730.571
If we take 21 away from 30, we end up with 9.
Since there are no more digits in the dividend, we add a zero to the remainder making it 90, and continue the process.

Going ahead to step 10:
If we divide 90 by 21, we get 4 and a remainder of 6.
Put 4 as the next digit of the answer. 
Result so far: 31730.5714
If we take 84 away from 90, we end up with 6.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

Advancing to step 11:
The number 21 fits into 60 2 times, leaving a remainder of 18.
Put 2 as the next digit of the answer. 
Result so far: 31730.57142
The remainder is 18 after subtracting 42 from 60.
Since there are no more digits in the dividend, we add a zero to the remainder making it 180, and continue the process.

Advancing to step 12:
180 divided by 21 is 8 with a remainder of 12.
The next digit of our result is 8. 
Result so far: 31730.571428
Subtract 168 from 180 to get 12.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

Let's proceed to step 13:
120 divided by 21 is 5 with a remainder of 15.
The number 5 becomes the next digit in our result. 
Result so far: 31730.5714285
Subtract 105 from 120 to get 15.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

Moving on to step 14:
When dividing 150 by 21, we get 7 with a remainder of 3.
Record the quotient 7 as the next digit in the result. 
Result so far: 31730.57142857
Subtract 147 from 150 to get 3.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

After the division, we end up with 31730.57142857 and a remainder of 3e-09.