Let's divide 403921 by 51
We want to figure out the number of times 403921 can be divided by 51.

On to step 1:
If we divide 4 by 51, we get 0 and a remainder of 4.
Put 0 as the next digit of the answer. 
Result so far: 0.0
The remainder is 4 after subtracting 0 from 4.
Include the next digit (0) from the dividend after 4, then repeat: 40 / 51

Step 2:
When dividing 40 by 51, we get 0 with a remainder of 40.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Deduct 0 from 40 and we're left with 40.
Include the next digit (3) from the dividend after 40, then repeat: 403 / 51

On to step 3:
51 goes into 403 7 times with a remainder of 46.
The number 7 becomes the next digit in our result. 
Result so far: 7.0
If we take 357 away from 403, we end up with 46.
Take the next digit (9) from the dividend and append it to 46, then repeat: 469 / 51

Advancing to step 4:
The number 51 fits into 469 9 times, leaving a remainder of 10.
The next digit of our result is 9. 
Result so far: 79.0
Subtract 459 from 469 to get 10.
Fetch the next digit (2) from the dividend, attach it to 10 and continue: 102 / 51

On to step 5:
51 can be fit into 102 2 times, resulting in a remainder of 0.
Write down 2 as next digit of the result. 
Result so far: 792.0
If we take 102 away from 102, we end up with 0.
Bring next digit (1) of the dividend behind the 0 and repeat the process: 1 / 51

On to step 6:
51 goes into 1 0 times with a remainder of 1.
The next digit of our result is 0. 
Result so far: 7920.0
Deduct 0 from 1 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.

Advancing to step 7:
51 goes into 10 0 times with a remainder of 10.
Put 0 as the next digit of the answer. 
Result so far: 7920.0
If we subtract 0 from 10, we get 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Going ahead to step 8:
The number 51 fits into 100 1 times, leaving a remainder of 49.
Use 1 as the next digit of our solution. 
Result so far: 7920.01
If we subtract 51 from 100, we get 49.
Since there are no more digits in the dividend, we add a zero to the remainder making it 490, and continue the process.

On to step 9:
51 goes into 490 9 times with a remainder of 31.
Write down 9 as next digit of the result. 
Result so far: 7920.019
Subtract 459 from 490 to get 31.
Since there are no more digits in the dividend, we add a zero to the remainder making it 310, and continue the process.

Going ahead to step 10:
The number 51 fits into 310 6 times, leaving a remainder of 4.
Record the quotient 6 as the next digit in the result. 
Result so far: 7920.0196
Deduct 306 from 310 and we're left 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.

Let's proceed to step 11:
When dividing 40 by 51, we get 0 with a remainder of 40.
Record the quotient 0 as the next digit in the result. 
Result so far: 7920.0196
Deduct 0 from 40 and we're left with 40.
Since there are no more digits in the dividend, we add a zero to the remainder making it 400, and continue the process.

Moving on to step 12:
51 can be fit into 400 7 times, resulting in a remainder of 43.
The number 7 becomes the next digit in our result. 
Result so far: 7920.019607
Subtract 357 from 400 to get 43.
Since there are no more digits in the dividend, we add a zero to the remainder making it 430, and continue the process.

Going ahead to step 13:
430 divided by 51 is 8 with a remainder of 22.
Record the quotient 8 as the next digit in the result. 
Result so far: 7920.0196078
If we take 408 away from 430, we end up with 22.
Since there are no more digits in the dividend, we add a zero to the remainder making it 220, and continue the process.

Advancing to step 14:
51 can be fit into 220 4 times, resulting in a remainder of 16.
The next digit of our result is 4. 
Result so far: 7920.01960784
Subtract 204 from 220 to get 16.
Since there are no more digits in the dividend, we add a zero to the remainder making it 160, and continue the process.

In conclusion, the division gives 7920.01960784 with a balance of 1.6e-08.