We look at the division of 421815 by 79 
Let's see how many times 79 fits into 421815.

Going ahead to step 1:
79 can be fit into 4 0 times, resulting in a remainder of 4.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we take 0 away from 4, we end up with 4.
Include the next digit (2) from the dividend after 4, then repeat: 42 / 79

Moving on to step 2:
The number 79 fits into 42 0 times, leaving a remainder of 42.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we take 0 away from 42, we end up with 42.
Bring next digit (1) of the dividend behind the 42 and repeat the process: 421 / 79

Let's proceed to step 3:
421 divided by 79 is 5 with a remainder of 26.
The number 5 becomes the next digit in our result. 
Result so far: 5.0
Subtract 395 from 421 to get 26.
Include the next digit (8) from the dividend after 26, then repeat: 268 / 79

Going ahead to step 4:
79 can be fit into 268 3 times, resulting in a remainder of 31.
Put 3 as the next digit of the answer. 
Result so far: 53.0
The remainder is 31 after subtracting 237 from 268.
Take the next digit (1) from the dividend and append it to 31, then repeat: 311 / 79

Step 5:
79 goes into 311 3 times with a remainder of 74.
Put 3 as the next digit of the answer. 
Result so far: 533.0
If we subtract 237 from 311, we get 74.
Grab the next digit (5) from the dividend, add it to 74, then carry on: 745 / 79

Step 6:
The number 79 fits into 745 9 times, leaving a remainder of 34.
Record the quotient 9 as the next digit in the result. 
Result so far: 5339.0
Subtract 711 from 745 to get 34.
Since there are no more digits in the dividend, we add a zero to the remainder making it 340, and continue the process.

On to step 7:
If we divide 340 by 79, we get 4 and a remainder of 24.
The next digit of our result is 4. 
Result so far: 5339.4
If we subtract 316 from 340, we get 24.
Since there are no more digits in the dividend, we add a zero to the remainder making it 240, and continue the process.

Let's proceed to step 8:
79 goes into 240 3 times with a remainder of 3.
The next digit of our result is 3. 
Result so far: 5339.43
If we subtract 237 from 240, we 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.

Step 9:
30 divided by 79 is 0 with a remainder of 30.
The number 0 becomes the next digit in our result. 
Result so far: 5339.43
If we take 0 away from 30, we end up with 30.
Since there are no more digits in the dividend, we add a zero to the remainder making it 300, and continue the process.

Going ahead to step 10:
If we divide 300 by 79, we get 3 and a remainder of 63.
Put 3 as the next digit of the answer. 
Result so far: 5339.4303
Subtracting 237 from 300 leaves us with 63.
Since there are no more digits in the dividend, we add a zero to the remainder making it 630, and continue the process.

Advancing to step 11:
The number 79 fits into 630 7 times, leaving a remainder of 77.
Use 7 as the next digit of our solution. 
Result so far: 5339.43037
Deduct 553 from 630 and we're left with 77.
Since there are no more digits in the dividend, we add a zero to the remainder making it 770, and continue the process.

Going ahead to step 12:
770 divided by 79 is 9 with a remainder of 59.
Use 9 as the next digit of our solution. 
Result so far: 5339.430379
If we take 711 away from 770, we end up with 59.
Since there are no more digits in the dividend, we add a zero to the remainder making it 590, and continue the process.

On to step 13:
79 can be fit into 590 7 times, resulting in a remainder of 37.
The next digit of our result is 7. 
Result so far: 5339.4303797
Subtract 553 from 590 to get 37.
Since there are no more digits in the dividend, we add a zero to the remainder making it 370, and continue the process.

On to step 14:
When dividing 370 by 79, we get 4 with a remainder of 54.
Use 4 as the next digit of our solution. 
Result so far: 5339.43037974
Subtract 316 from 370 to get 54.
Since there are no more digits in the dividend, we add a zero to the remainder making it 540, and continue the process.

After the division, we end up with 5339.43037974 and a remainder of 5.4e-08.