We look at the division of 87358987 by 431 
The aim is to understand the frequency of 431 in 87358987.

On to step 1:
8 divided by 431 is 0 with a remainder of 8.
The next digit of our result is 0. 
Result so far: 0.0
Deduct 0 from 8 and we're left with 8.
Grab the next digit (7) from the dividend, add it to 8, then carry on: 87 / 431

Going ahead to step 2:
When dividing 87 by 431, we get 0 with a remainder of 87.
The next digit of our result is 0. 
Result so far: 0.0
Deduct 0 from 87 and we're left with 87.
Append the next digit (3) from the dividend to 87 and continue with: 873 / 431

Moving on to step 3:
The number 431 fits into 873 2 times, leaving a remainder of 11.
The next digit of our result is 2. 
Result so far: 2.0
If we take 862 away from 873, we end up with 11.
Fetch the next digit (5) from the dividend, attach it to 11 and continue: 115 / 431

Step 4:
115 divided by 431 is 0 with a remainder of 115.
The next digit of our result is 0. 
Result so far: 20.0
If we subtract 0 from 115, we get 115.
Include the next digit (8) from the dividend after 115, then repeat: 1158 / 431

Going ahead to step 5:
If we divide 1158 by 431, we get 2 and a remainder of 296.
Write down 2 as next digit of the result. 
Result so far: 202.0
Subtracting 862 from 1158 leaves us with 296.
Bring next digit (9) of the dividend behind the 296 and repeat the process: 2969 / 431

Moving on to step 6:
When dividing 2969 by 431, we get 6 with a remainder of 383.
Put 6 as the next digit of the answer. 
Result so far: 2026.0
Deduct 2586 from 2969 and we're left with 383.
Append the next digit (8) from the dividend to 383 and continue with: 3838 / 431

Moving on to step 7:
If we divide 3838 by 431, we get 8 and a remainder of 390.
The next digit of our result is 8. 
Result so far: 20268.0
Subtracting 3448 from 3838 leaves us with 390.
Take the next digit (7) from the dividend and append it to 390, then repeat: 3907 / 431

Going ahead to step 8:
3907 divided by 431 is 9 with a remainder of 28.
Put 9 as the next digit of the answer. 
Result so far: 202689.0
If we take 3879 away from 3907, we end up with 28.
Since there are no more digits in the dividend, we add a zero to the remainder making it 280, and continue the process.

Going ahead to step 9:
431 can be fit into 280 0 times, resulting in a remainder of 280.
Record the quotient 0 as the next digit in the result. 
Result so far: 202689.0
If we subtract 0 from 280, we get 280.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2800, and continue the process.

On to step 10:
If we divide 2800 by 431, we get 6 and a remainder of 214.
The number 6 becomes the next digit in our result. 
Result so far: 202689.06
If we subtract 2586 from 2800, we get 214.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2140, and continue the process.

Going ahead to step 11:
The number 431 fits into 2140 4 times, leaving a remainder of 416.
The number 4 becomes the next digit in our result. 
Result so far: 202689.064
If we take 1724 away from 2140, we end up with 416.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4160, and continue the process.

On to step 12:
If we divide 4160 by 431, we get 9 and a remainder of 281.
Write down 9 as next digit of the result. 
Result so far: 202689.0649
The remainder is 281 after subtracting 3879 from 4160.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2810, and continue the process.

Advancing to step 13:
The number 431 fits into 2810 6 times, leaving a remainder of 224.
The next digit of our result is 6. 
Result so far: 202689.06496
If we subtract 2586 from 2810, we get 224.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2240, and continue the process.

Going ahead to step 14:
When dividing 2240 by 431, we get 5 with a remainder of 85.
Record the quotient 5 as the next digit in the result. 
Result so far: 202689.064965
Deduct 2155 from 2240 and we're left with 85.
Since there are no more digits in the dividend, we add a zero to the remainder making it 850, and continue the process.

On to step 15:
850 divided by 431 is 1 with a remainder of 419.
Use 1 as the next digit of our solution. 
Result so far: 202689.0649651
Subtract 431 from 850 to get 419.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4190, and continue the process.

Let's proceed to step 16:
431 goes into 4190 9 times with a remainder of 311.
The number 9 becomes the next digit in our result. 
Result so far: 202689.06496519
If we take 3879 away from 4190, we end up with 311.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3110, and continue the process.

The final result is 202689.06496519 with a remainder of 3.11e-07.