We're dividing 12365902 by 409 
The aim is to understand the frequency of 409 in 12365902.

Let's proceed to step 1:
If we divide 1 by 409, we get 0 and a remainder of 1.
Use 0 as the next digit of our solution. 
Result so far: 0.0
If we subtract 0 from 1, we get 1.
Grab the next digit (2) from the dividend, add it to 1, then carry on: 12 / 409

Step 2:
409 goes into 12 0 times with a remainder of 12.
Write down 0 as next digit of the result. 
Result so far: 0.0
If we subtract 0 from 12, we get 12.
Fetch the next digit (3) from the dividend, attach it to 12 and continue: 123 / 409

On to step 3:
409 can be fit into 123 0 times, resulting in a remainder of 123.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtracting 0 from 123 leaves us with 123.
Take the next digit (6) from the dividend and append it to 123, then repeat: 1236 / 409

Let's proceed to step 4:
The number 409 fits into 1236 3 times, leaving a remainder of 9.
The next digit of our result is 3. 
Result so far: 3.0
The remainder is 9 after subtracting 1227 from 1236.
Bring next digit (5) of the dividend behind the 9 and repeat the process: 95 / 409

Let's proceed to step 5:
409 can be fit into 95 0 times, resulting in a remainder of 95.
Record the quotient 0 as the next digit in the result. 
Result so far: 30.0
If we take 0 away from 95, we end up with 95.
Fetch the next digit (9) from the dividend, attach it to 95 and continue: 959 / 409

Moving on to step 6:
959 divided by 409 is 2 with a remainder of 141.
Record the quotient 2 as the next digit in the result. 
Result so far: 302.0
Subtracting 818 from 959 leaves us with 141.
Grab the next digit (0) from the dividend, add it to 141, then carry on: 1410 / 409

Let's proceed to step 7:
409 goes into 1410 3 times with a remainder of 183.
The number 3 becomes the next digit in our result. 
Result so far: 3023.0
Subtract 1227 from 1410 to get 183.
Bring next digit (2) of the dividend behind the 183 and repeat the process: 1832 / 409

Advancing to step 8:
If we divide 1832 by 409, we get 4 and a remainder of 196.
Use 4 as the next digit of our solution. 
Result so far: 30234.0
Deduct 1636 from 1832 and we're left with 196.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1960, and continue the process.

Advancing to step 9:
When dividing 1960 by 409, we get 4 with a remainder of 324.
Put 4 as the next digit of the answer. 
Result so far: 30234.4
Subtract 1636 from 1960 to get 324.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3240, and continue the process.

Moving on to step 10:
409 can be fit into 3240 7 times, resulting in a remainder of 377.
The next digit of our result is 7. 
Result so far: 30234.47
Deduct 2863 from 3240 and we're left with 377.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3770, and continue the process.

On to step 11:
409 goes into 3770 9 times with a remainder of 89.
Record the quotient 9 as the next digit in the result. 
Result so far: 30234.479
Subtracting 3681 from 3770 leaves us with 89.
Since there are no more digits in the dividend, we add a zero to the remainder making it 890, and continue the process.

On to step 12:
If we divide 890 by 409, we get 2 and a remainder of 72.
The next digit of our result is 2. 
Result so far: 30234.4792
Subtracting 818 from 890 leaves us with 72.
Since there are no more digits in the dividend, we add a zero to the remainder making it 720, and continue the process.

Step 13:
The number 409 fits into 720 1 times, leaving a remainder of 311.
Use 1 as the next digit of our solution. 
Result so far: 30234.47921
The remainder is 311 after subtracting 409 from 720.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3110, and continue the process.

Advancing to step 14:
409 goes into 3110 7 times with a remainder of 247.
The next digit of our result is 7. 
Result so far: 30234.479217
Subtract 2863 from 3110 to get 247.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2470, and continue the process.

Advancing to step 15:
When dividing 2470 by 409, we get 6 with a remainder of 16.
Use 6 as the next digit of our solution. 
Result so far: 30234.4792176
If we take 2454 away from 2470, we end up with 16.
Since there are no more digits in the dividend, we add a zero to the remainder making it 160, and continue the process.

Moving on to step 16:
409 goes into 160 0 times with a remainder of 160.
The number 0 becomes the next digit in our result. 
Result so far: 30234.4792176
Subtracting 0 from 160 leaves us with 160.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1600, and continue the process.

After the division, we end up with 30234.4792176 and a remainder of 1.6e-07.