666755 divided by 21 
Let's see how many times 21 fits into 666755.

Going ahead to step 1:
21 goes into 6 0 times with a remainder of 6.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
If we take 0 away from 6, we end up with 6.
Take the next digit (6) from the dividend and append it to 6, then repeat: 66 / 21

Advancing to step 2:
If we divide 66 by 21, we get 3 and a remainder of 3.
The number 3 becomes the next digit in our result. 
Result so far: 3.0
Subtract 63 from 66 to get 3.
Take the next digit (6) from the dividend and append it to 3, then repeat: 36 / 21

Going ahead to step 3:
The number 21 fits into 36 1 times, leaving a remainder of 15.
The number 1 becomes the next digit in our result. 
Result so far: 31.0
Subtract 21 from 36 to get 15.
Append the next digit (7) from the dividend to 15 and continue with: 157 / 21

Step 4:
The number 21 fits into 157 7 times, leaving a remainder of 10.
Put 7 as the next digit of the answer. 
Result so far: 317.0
If we take 147 away from 157, we end up with 10.
Grab the next digit (5) from the dividend, add it to 10, then carry on: 105 / 21

Step 5:
When dividing 105 by 21, we get 5 with a remainder of 0.
Use 5 as the next digit of our solution. 
Result so far: 3175.0
If we take 105 away from 105, we end up with 0.
Include the next digit (5) from the dividend after 0, then repeat: 5 / 21

Moving on to step 6:
21 goes into 5 0 times with a remainder of 5.
Record the quotient 0 as the next digit in the result. 
Result so far: 31750.0
Subtracting 0 from 5 leaves us 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.

Step 7:
21 can be fit into 50 2 times, resulting in a remainder of 8.
Write down 2 as next digit of the result. 
Result so far: 31750.2
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 8:
80 divided by 21 is 3 with a remainder of 17.
The number 3 becomes the next digit in our result. 
Result so far: 31750.23
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.

On to step 9:
21 can be fit into 170 8 times, resulting in a remainder of 2.
The number 8 becomes the next digit in our result. 
Result so far: 31750.238
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.

Advancing to step 10:
21 can be fit into 20 0 times, resulting in a remainder of 20.
The number 0 becomes the next digit in our result. 
Result so far: 31750.238
Subtract 0 from 20 to 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.

Moving on to step 11:
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: 31750.23809
If we take 189 away from 200, we end up 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.

Let's proceed to step 12:
The number 21 fits into 110 5 times, leaving a remainder of 5.
Put 5 as the next digit of the answer. 
Result so far: 31750.238095
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.

Moving on to step 13:
The number 21 fits into 50 2 times, leaving a remainder of 8.
Put 2 as the next digit of the answer. 
Result so far: 31750.2380952
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.

On to step 14:
80 divided by 21 is 3 with a remainder of 17.
Write down 3 as next digit of the result. 
Result so far: 31750.23809523
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.

The final outcome is 31750.23809523, with a leftover of 1.7e-08.