We look at the division of 90507231 by 843 
The aim is to understand the frequency of 843 in 90507231.

Step 1:
The number 843 fits into 9 0 times, leaving a remainder of 9.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Subtracting 0 from 9 leaves us with 9.
Fetch the next digit (0) from the dividend, attach it to 9 and continue: 90 / 843

Going ahead to step 2:
90 divided by 843 is 0 with a remainder of 90.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtracting 0 from 90 leaves us with 90.
Take the next digit (5) from the dividend and append it to 90, then repeat: 905 / 843

Advancing to step 3:
The number 843 fits into 905 1 times, leaving a remainder of 62.
Record the quotient 1 as the next digit in the result. 
Result so far: 1.0
Subtract 843 from 905 to get 62.
Grab the next digit (0) from the dividend, add it to 62, then carry on: 620 / 843

Advancing to step 4:
When dividing 620 by 843, we get 0 with a remainder of 620.
The number 0 becomes the next digit in our result. 
Result so far: 10.0
Subtracting 0 from 620 leaves us with 620.
Grab the next digit (7) from the dividend, add it to 620, then carry on: 6207 / 843

Advancing to step 5:
843 goes into 6207 7 times with a remainder of 306.
Put 7 as the next digit of the answer. 
Result so far: 107.0
If we subtract 5901 from 6207, we get 306.
Take the next digit (2) from the dividend and append it to 306, then repeat: 3062 / 843

Going ahead to step 6:
843 can be fit into 3062 3 times, resulting in a remainder of 533.
Put 3 as the next digit of the answer. 
Result so far: 1073.0
Subtracting 2529 from 3062 leaves us with 533.
Grab the next digit (3) from the dividend, add it to 533, then carry on: 5333 / 843

Moving on to step 7:
The number 843 fits into 5333 6 times, leaving a remainder of 275.
Put 6 as the next digit of the answer. 
Result so far: 10736.0
Deduct 5058 from 5333 and we're left with 275.
Grab the next digit (1) from the dividend, add it to 275, then carry on: 2751 / 843

On to step 8:
If we divide 2751 by 843, we get 3 and a remainder of 222.
Put 3 as the next digit of the answer. 
Result so far: 107363.0
Deduct 2529 from 2751 and we're left 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.

Let's proceed to step 9:
843 goes into 2220 2 times with a remainder of 534.
The next digit of our result is 2. 
Result so far: 107363.2
Deduct 1686 from 2220 and we're left with 534.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5340, and continue the process.

Advancing to step 10:
843 goes into 5340 6 times with a remainder of 282.
The next digit of our result is 6. 
Result so far: 107363.26
Deduct 5058 from 5340 and we're left with 282.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2820, and continue the process.

Let's proceed to step 11:
If we divide 2820 by 843, we get 3 and a remainder of 291.
The number 3 becomes the next digit in our result. 
Result so far: 107363.263
Subtracting 2529 from 2820 leaves us with 291.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2910, and continue the process.

Going ahead to step 12:
When dividing 2910 by 843, we get 3 with a remainder of 381.
The number 3 becomes the next digit in our result. 
Result so far: 107363.2633
Deduct 2529 from 2910 and we're left with 381.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3810, and continue the process.

The final result is 107363.2633 with a remainder of 0.00381.