We're dividing 86597748 by 991 
The aim is to understand the frequency of 991 in 86597748.

Step 1:
The number 991 fits into 8 0 times, leaving a remainder of 8.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
The remainder is 8 after subtracting 0 from 8.
Fetch the next digit (6) from the dividend, attach it to 8 and continue: 86 / 991

Moving on to step 2:
When dividing 86 by 991, we get 0 with a remainder of 86.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we subtract 0 from 86, we get 86.
Append the next digit (5) from the dividend to 86 and continue with: 865 / 991

Let's proceed to step 3:
991 can be fit into 865 0 times, resulting in a remainder of 865.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we subtract 0 from 865, we get 865.
Grab the next digit (9) from the dividend, add it to 865, then carry on: 8659 / 991

Step 4:
If we divide 8659 by 991, we get 8 and a remainder of 731.
Record the quotient 8 as the next digit in the result. 
Result so far: 8.0
The remainder is 731 after subtracting 7928 from 8659.
Grab the next digit (7) from the dividend, add it to 731, then carry on: 7317 / 991

On to step 5:
The number 991 fits into 7317 7 times, leaving a remainder of 380.
Use 7 as the next digit of our solution. 
Result so far: 87.0
If we take 6937 away from 7317, we end up with 380.
Grab the next digit (7) from the dividend, add it to 380, then carry on: 3807 / 991

Step 6:
If we divide 3807 by 991, we get 3 and a remainder of 834.
Use 3 as the next digit of our solution. 
Result so far: 873.0
Subtract 2973 from 3807 to get 834.
Bring next digit (4) of the dividend behind the 834 and repeat the process: 8344 / 991

Going ahead to step 7:
If we divide 8344 by 991, we get 8 and a remainder of 416.
Write down 8 as next digit of the result. 
Result so far: 8738.0
Subtract 7928 from 8344 to get 416.
Bring next digit (8) of the dividend behind the 416 and repeat the process: 4168 / 991

Going ahead to step 8:
The number 991 fits into 4168 4 times, leaving a remainder of 204.
Use 4 as the next digit of our solution. 
Result so far: 87384.0
Deduct 3964 from 4168 and we're left with 204.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2040, and continue the process.

Step 9:
991 can be fit into 2040 2 times, resulting in a remainder of 58.
The next digit of our result is 2. 
Result so far: 87384.2
If we take 1982 away from 2040, we end up with 58.
Since there are no more digits in the dividend, we add a zero to the remainder making it 580, and continue the process.

On to step 10:
When dividing 580 by 991, we get 0 with a remainder of 580.
The number 0 becomes the next digit in our result. 
Result so far: 87384.2
If we take 0 away from 580, we end up with 580.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5800, and continue the process.

Going ahead to step 11:
When dividing 5800 by 991, we get 5 with a remainder of 845.
Use 5 as the next digit of our solution. 
Result so far: 87384.205
The remainder is 845 after subtracting 4955 from 5800.
Since there are no more digits in the dividend, we add a zero to the remainder making it 8450, and continue the process.

Let's proceed to step 12:
If we divide 8450 by 991, we get 8 and a remainder of 522.
Record the quotient 8 as the next digit in the result. 
Result so far: 87384.2058
Subtracting 7928 from 8450 leaves us with 522.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5220, and continue the process.

Advancing to step 13:
5220 divided by 991 is 5 with a remainder of 265.
Write down 5 as next digit of the result. 
Result so far: 87384.20585
Subtracting 4955 from 5220 leaves us with 265.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2650, and continue the process.

Step 14:
When dividing 2650 by 991, we get 2 with a remainder of 668.
Put 2 as the next digit of the answer. 
Result so far: 87384.205852
Deduct 1982 from 2650 and we're left with 668.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6680, and continue the process.

Moving on to step 15:
If we divide 6680 by 991, we get 6 and a remainder of 734.
Record the quotient 6 as the next digit in the result. 
Result so far: 87384.2058526
Subtract 5946 from 6680 to get 734.
Since there are no more digits in the dividend, we add a zero to the remainder making it 7340, and continue the process.

Advancing to step 16:
991 can be fit into 7340 7 times, resulting in a remainder of 403.
The number 7 becomes the next digit in our result. 
Result so far: 87384.20585267
If we subtract 6937 from 7340, we get 403.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4030, and continue the process.

The final result is 87384.20585267 with a remainder of 4.03e-07.