Let's divide 4291389 by 420
We want to figure out the number of times 4291389 can be divided by 420.

Step 1:
4 divided by 420 is 0 with a remainder of 4.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Subtract 0 from 4 to get 4.
Fetch the next digit (2) from the dividend, attach it to 4 and continue: 42 / 420

Advancing to step 2:
42 divided by 420 is 0 with a remainder of 42.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Subtract 0 from 42 to get 42.
Fetch the next digit (9) from the dividend, attach it to 42 and continue: 429 / 420

Step 3:
429 divided by 420 is 1 with a remainder of 9.
The number 1 becomes the next digit in our result. 
Result so far: 1.0
Deduct 420 from 429 and we're left with 9.
Append the next digit (1) from the dividend to 9 and continue with: 91 / 420

Moving on to step 4:
When dividing 91 by 420, we get 0 with a remainder of 91.
Use 0 as the next digit of our solution. 
Result so far: 10.0
Subtract 0 from 91 to get 91.
Append the next digit (3) from the dividend to 91 and continue with: 913 / 420

Step 5:
When dividing 913 by 420, we get 2 with a remainder of 73.
The number 2 becomes the next digit in our result. 
Result so far: 102.0
If we take 840 away from 913, we end up with 73.
Include the next digit (8) from the dividend after 73, then repeat: 738 / 420

Step 6:
When dividing 738 by 420, we get 1 with a remainder of 318.
The number 1 becomes the next digit in our result. 
Result so far: 1021.0
The remainder is 318 after subtracting 420 from 738.
Bring next digit (9) of the dividend behind the 318 and repeat the process: 3189 / 420

Moving on to step 7:
The number 420 fits into 3189 7 times, leaving a remainder of 249.
Use 7 as the next digit of our solution. 
Result so far: 10217.0
Deduct 2940 from 3189 and we're left with 249.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2490, and continue the process.

Let's proceed to step 8:
2490 divided by 420 is 5 with a remainder of 390.
Use 5 as the next digit of our solution. 
Result so far: 10217.5
Subtracting 2100 from 2490 leaves us with 390.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3900, and continue the process.

Let's proceed to step 9:
420 goes into 3900 9 times with a remainder of 120.
Write down 9 as next digit of the result. 
Result so far: 10217.59
Subtract 3780 from 3900 to get 120.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1200, and continue the process.

On to step 10:
420 can be fit into 1200 2 times, resulting in a remainder of 360.
Write down 2 as next digit of the result. 
Result so far: 10217.592
If we subtract 840 from 1200, we get 360.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3600, and continue the process.

Advancing to step 11:
420 goes into 3600 8 times with a remainder of 240.
Put 8 as the next digit of the answer. 
Result so far: 10217.5928
If we subtract 3360 from 3600, we get 240.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2400, and continue the process.

On to step 12:
2400 divided by 420 is 5 with a remainder of 300.
The next digit of our result is 5. 
Result so far: 10217.59285
Subtract 2100 from 2400 to get 300.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3000, and continue the process.

Advancing to step 13:
3000 divided by 420 is 7 with a remainder of 60.
Use 7 as the next digit of our solution. 
Result so far: 10217.592857
If we subtract 2940 from 3000, we get 60.
Since there are no more digits in the dividend, we add a zero to the remainder making it 600, and continue the process.

Advancing to step 14:
420 goes into 600 1 times with a remainder of 180.
The next digit of our result is 1. 
Result so far: 10217.5928571
Subtracting 420 from 600 leaves us with 180.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1800, and continue the process.

On to step 15:
The number 420 fits into 1800 4 times, leaving a remainder of 120.
Put 4 as the next digit of the answer. 
Result so far: 10217.59285714
Subtracting 1680 from 1800 leaves us with 120.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1200, and continue the process.

In conclusion, the division gives 10217.59285714 with a balance of 1.2e-07.