We're dividing 321972 by 21 
We're looking to find how many times 21 goes into 321972.

Moving on to step 1:
21 goes into 3 0 times with a remainder of 3.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtracting 0 from 3 leaves us with 3.
Fetch the next digit (2) from the dividend, attach it to 3 and continue: 32 / 21

Going ahead to step 2:
If we divide 32 by 21, we get 1 and a remainder of 11.
Put 1 as the next digit of the answer. 
Result so far: 1.0
If we take 21 away from 32, we end up with 11.
Grab the next digit (1) from the dividend, add it to 11, then carry on: 111 / 21

Moving on to step 3:
21 goes into 111 5 times with a remainder of 6.
Use 5 as the next digit of our solution. 
Result so far: 15.0
If we take 105 away from 111, we end up with 6.
Append the next digit (9) from the dividend to 6 and continue with: 69 / 21

Step 4:
21 goes into 69 3 times with a remainder of 6.
The number 3 becomes the next digit in our result. 
Result so far: 153.0
If we subtract 63 from 69, we get 6.
Grab the next digit (7) from the dividend, add it to 6, then carry on: 67 / 21

Let's proceed to step 5:
21 can be fit into 67 3 times, resulting in a remainder of 4.
The next digit of our result is 3. 
Result so far: 1533.0
If we subtract 63 from 67, we get 4.
Take the next digit (2) from the dividend and append it to 4, then repeat: 42 / 21

On to step 6:
42 divided by 21 is 2 with a remainder of 0.
Put 2 as the next digit of the answer. 
Result so far: 15332.0
If we take 42 away from 42, we end up with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Step 7:
21 goes into 0 0 times with a remainder of 0.
Put 0 as the next digit of the answer. 
Result so far: 15332.0
Deduct 0 from 0 and we're left with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

On to step 8:
21 goes into 0 0 times with a remainder of 0.
The next digit of our result is 0. 
Result so far: 15332.0
Deduct 0 from 0 and we're left with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

The quotient of the division is 15332.0, and the remainder is 0.0.