51255955 divided by 421 
Let's see how many times 421 fits into 51255955.

Advancing to step 1:
421 goes into 5 0 times with a remainder of 5.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Subtracting 0 from 5 leaves us with 5.
Grab the next digit (1) from the dividend, add it to 5, then carry on: 51 / 421

Step 2:
If we divide 51 by 421, we get 0 and a remainder of 51.
The next digit of our result is 0. 
Result so far: 0.0
If we take 0 away from 51, we end up with 51.
Fetch the next digit (2) from the dividend, attach it to 51 and continue: 512 / 421

Step 3:
The number 421 fits into 512 1 times, leaving a remainder of 91.
The next digit of our result is 1. 
Result so far: 1.0
The remainder is 91 after subtracting 421 from 512.
Include the next digit (5) from the dividend after 91, then repeat: 915 / 421

Going ahead to step 4:
If we divide 915 by 421, we get 2 and a remainder of 73.
The number 2 becomes the next digit in our result. 
Result so far: 12.0
If we take 842 away from 915, we end up with 73.
Take the next digit (5) from the dividend and append it to 73, then repeat: 735 / 421

Step 5:
421 can be fit into 735 1 times, resulting in a remainder of 314.
Use 1 as the next digit of our solution. 
Result so far: 121.0
Subtracting 421 from 735 leaves us with 314.
Bring next digit (9) of the dividend behind the 314 and repeat the process: 3149 / 421

Advancing to step 6:
The number 421 fits into 3149 7 times, leaving a remainder of 202.
Use 7 as the next digit of our solution. 
Result so far: 1217.0
If we take 2947 away from 3149, we end up with 202.
Append the next digit (5) from the dividend to 202 and continue with: 2025 / 421

Advancing to step 7:
If we divide 2025 by 421, we get 4 and a remainder of 341.
Write down 4 as next digit of the result. 
Result so far: 12174.0
If we subtract 1684 from 2025, we get 341.
Append the next digit (5) from the dividend to 341 and continue with: 3415 / 421

Let's proceed to step 8:
When dividing 3415 by 421, we get 8 with a remainder of 47.
Put 8 as the next digit of the answer. 
Result so far: 121748.0
If we take 3368 away from 3415, we end up with 47.
Since there are no more digits in the dividend, we add a zero to the remainder making it 470, and continue the process.

Step 9:
When dividing 470 by 421, we get 1 with a remainder of 49.
Put 1 as the next digit of the answer. 
Result so far: 121748.1
Subtracting 421 from 470 leaves us with 49.
Since there are no more digits in the dividend, we add a zero to the remainder making it 490, and continue the process.

Advancing to step 10:
The number 421 fits into 490 1 times, leaving a remainder of 69.
Use 1 as the next digit of our solution. 
Result so far: 121748.11
Subtracting 421 from 490 leaves us with 69.
Since there are no more digits in the dividend, we add a zero to the remainder making it 690, and continue the process.

Our division results in 121748.11 with a remaining 0.069.