We're dividing 80903691 by 431 
The aim is to understand the frequency of 431 in 80903691.

Let's proceed to step 1:
The number 431 fits into 8 0 times, leaving a remainder of 8.
Use 0 as the next digit of our solution. 
Result so far: 0.0
If we take 0 away from 8, we end up with 8.
Bring next digit (0) of the dividend behind the 8 and repeat the process: 80 / 431

Moving on to step 2:
431 can be fit into 80 0 times, resulting in a remainder of 80.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we subtract 0 from 80, we get 80.
Append the next digit (9) from the dividend to 80 and continue with: 809 / 431

On to step 3:
The number 431 fits into 809 1 times, leaving a remainder of 378.
Put 1 as the next digit of the answer. 
Result so far: 1.0
If we subtract 431 from 809, we get 378.
Bring next digit (0) of the dividend behind the 378 and repeat the process: 3780 / 431

Advancing to step 4:
If we divide 3780 by 431, we get 8 and a remainder of 332.
Record the quotient 8 as the next digit in the result. 
Result so far: 18.0
Deduct 3448 from 3780 and we're left with 332.
Grab the next digit (3) from the dividend, add it to 332, then carry on: 3323 / 431

Going ahead to step 5:
If we divide 3323 by 431, we get 7 and a remainder of 306.
The next digit of our result is 7. 
Result so far: 187.0
The remainder is 306 after subtracting 3017 from 3323.
Take the next digit (6) from the dividend and append it to 306, then repeat: 3066 / 431

On to step 6:
If we divide 3066 by 431, we get 7 and a remainder of 49.
Record the quotient 7 as the next digit in the result. 
Result so far: 1877.0
Deduct 3017 from 3066 and we're left with 49.
Append the next digit (9) from the dividend to 49 and continue with: 499 / 431

Advancing to step 7:
If we divide 499 by 431, we get 1 and a remainder of 68.
Write down 1 as next digit of the result. 
Result so far: 18771.0
If we subtract 431 from 499, we get 68.
Fetch the next digit (1) from the dividend, attach it to 68 and continue: 681 / 431

Going ahead to step 8:
If we divide 681 by 431, we get 1 and a remainder of 250.
Write down 1 as next digit of the result. 
Result so far: 187711.0
If we take 431 away from 681, we end up with 250.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2500, and continue the process.

Going ahead to step 9:
2500 divided by 431 is 5 with a remainder of 345.
Put 5 as the next digit of the answer. 
Result so far: 187711.5
If we take 2155 away from 2500, we end up with 345.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3450, and continue the process.

Let's proceed to step 10:
The number 431 fits into 3450 8 times, leaving a remainder of 2.
The number 8 becomes the next digit in our result. 
Result so far: 187711.58
The remainder is 2 after subtracting 3448 from 3450.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

Advancing to step 11:
431 goes into 20 0 times with a remainder of 20.
The number 0 becomes the next digit in our result. 
Result so far: 187711.58
Subtract 0 from 20 to get 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

On to step 12:
431 can be fit into 200 0 times, resulting in a remainder of 200.
The number 0 becomes the next digit in our result. 
Result so far: 187711.58
If we subtract 0 from 200, we get 200.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2000, and continue the process.

The final outcome is 187711.58, with a leftover of 0.002.