We look at the division of 15948435 by 309 
The aim is to understand the frequency of 309 in 15948435.

Let's proceed to step 1:
When dividing 1 by 309, we get 0 with a remainder of 1.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtracting 0 from 1 leaves us with 1.
Take the next digit (5) from the dividend and append it to 1, then repeat: 15 / 309

Let's proceed to step 2:
309 can be fit into 15 0 times, resulting in a remainder of 15.
The next digit of our result is 0. 
Result so far: 0.0
If we subtract 0 from 15, we get 15.
Bring next digit (9) of the dividend behind the 15 and repeat the process: 159 / 309

On to step 3:
When dividing 159 by 309, we get 0 with a remainder of 159.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
The remainder is 159 after subtracting 0 from 159.
Append the next digit (4) from the dividend to 159 and continue with: 1594 / 309

Let's proceed to step 4:
The number 309 fits into 1594 5 times, leaving a remainder of 49.
The next digit of our result is 5. 
Result so far: 5.0
If we subtract 1545 from 1594, we get 49.
Fetch the next digit (8) from the dividend, attach it to 49 and continue: 498 / 309

Going ahead to step 5:
The number 309 fits into 498 1 times, leaving a remainder of 189.
The next digit of our result is 1. 
Result so far: 51.0
The remainder is 189 after subtracting 309 from 498.
Grab the next digit (4) from the dividend, add it to 189, then carry on: 1894 / 309

On to step 6:
309 can be fit into 1894 6 times, resulting in a remainder of 40.
Use 6 as the next digit of our solution. 
Result so far: 516.0
Subtracting 1854 from 1894 leaves us with 40.
Grab the next digit (3) from the dividend, add it to 40, then carry on: 403 / 309

Let's proceed to step 7:
309 goes into 403 1 times with a remainder of 94.
The number 1 becomes the next digit in our result. 
Result so far: 5161.0
If we subtract 309 from 403, we get 94.
Fetch the next digit (5) from the dividend, attach it to 94 and continue: 945 / 309

Moving on to step 8:
309 can be fit into 945 3 times, resulting in a remainder of 18.
Put 3 as the next digit of the answer. 
Result so far: 51613.0
Subtracting 927 from 945 leaves us with 18.
Since there are no more digits in the dividend, we add a zero to the remainder making it 180, and continue the process.

On to step 9:
180 divided by 309 is 0 with a remainder of 180.
Record the quotient 0 as the next digit in the result. 
Result so far: 51613.0
Deduct 0 from 180 and we're left 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.

Advancing to step 10:
309 can be fit into 1800 5 times, resulting in a remainder of 255.
Use 5 as the next digit of our solution. 
Result so far: 51613.05
The remainder is 255 after subtracting 1545 from 1800.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2550, and continue the process.

Step 11:
When dividing 2550 by 309, we get 8 with a remainder of 78.
The next digit of our result is 8. 
Result so far: 51613.058
Deduct 2472 from 2550 and we're left with 78.
Since there are no more digits in the dividend, we add a zero to the remainder making it 780, and continue the process.

On to step 12:
If we divide 780 by 309, we get 2 and a remainder of 162.
The number 2 becomes the next digit in our result. 
Result so far: 51613.0582
Subtracting 618 from 780 leaves us with 162.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1620, and continue the process.

Moving on to step 13:
If we divide 1620 by 309, we get 5 and a remainder of 75.
Use 5 as the next digit of our solution. 
Result so far: 51613.05825
If we subtract 1545 from 1620, we get 75.
Since there are no more digits in the dividend, we add a zero to the remainder making it 750, and continue the process.

On to step 14:
309 can be fit into 750 2 times, resulting in a remainder of 132.
The number 2 becomes the next digit in our result. 
Result so far: 51613.058252
Subtracting 618 from 750 leaves us with 132.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1320, and continue the process.

Going ahead to step 15:
309 can be fit into 1320 4 times, resulting in a remainder of 84.
Use 4 as the next digit of our solution. 
Result so far: 51613.0582524
Subtracting 1236 from 1320 leaves us with 84.
Since there are no more digits in the dividend, we add a zero to the remainder making it 840, and continue the process.

Going ahead to step 16:
840 divided by 309 is 2 with a remainder of 222.
The number 2 becomes the next digit in our result. 
Result so far: 51613.05825242
Subtracting 618 from 840 leaves us with 222.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2220, and continue the process.

After the division, we end up with 51613.05825242 and a remainder of 2.22e-07.