78509794 divided by 91 
The aim is to understand the frequency of 91 in 78509794.

On to step 1:
91 can be fit into 7 0 times, resulting in a remainder of 7.
The next digit of our result is 0. 
Result so far: 0.0
Subtracting 0 from 7 leaves us with 7.
Bring next digit (8) of the dividend behind the 7 and repeat the process: 78 / 91

Going ahead to step 2:
If we divide 78 by 91, we get 0 and a remainder of 78.
Use 0 as the next digit of our solution. 
Result so far: 0.0
The remainder is 78 after subtracting 0 from 78.
Fetch the next digit (5) from the dividend, attach it to 78 and continue: 785 / 91

On to step 3:
91 goes into 785 8 times with a remainder of 57.
The number 8 becomes the next digit in our result. 
Result so far: 8.0
If we take 728 away from 785, we end up with 57.
Fetch the next digit (0) from the dividend, attach it to 57 and continue: 570 / 91

Going ahead to step 4:
When dividing 570 by 91, we get 6 with a remainder of 24.
Record the quotient 6 as the next digit in the result. 
Result so far: 86.0
Subtract 546 from 570 to get 24.
Append the next digit (9) from the dividend to 24 and continue with: 249 / 91

On to step 5:
The number 91 fits into 249 2 times, leaving a remainder of 67.
Record the quotient 2 as the next digit in the result. 
Result so far: 862.0
If we take 182 away from 249, we end up with 67.
Bring next digit (7) of the dividend behind the 67 and repeat the process: 677 / 91

Moving on to step 6:
The number 91 fits into 677 7 times, leaving a remainder of 40.
Write down 7 as next digit of the result. 
Result so far: 8627.0
If we take 637 away from 677, we end up with 40.
Fetch the next digit (9) from the dividend, attach it to 40 and continue: 409 / 91

Moving on to step 7:
91 goes into 409 4 times with a remainder of 45.
The number 4 becomes the next digit in our result. 
Result so far: 86274.0
Subtracting 364 from 409 leaves us with 45.
Bring next digit (4) of the dividend behind the 45 and repeat the process: 454 / 91

Advancing to step 8:
454 divided by 91 is 4 with a remainder of 90.
The next digit of our result is 4. 
Result so far: 862744.0
Subtract 364 from 454 to get 90.
Since there are no more digits in the dividend, we add a zero to the remainder making it 900, and continue the process.

On to step 9:
900 divided by 91 is 9 with a remainder of 81.
Use 9 as the next digit of our solution. 
Result so far: 862744.9
Deduct 819 from 900 and we're left with 81.
Since there are no more digits in the dividend, we add a zero to the remainder making it 810, and continue the process.

Moving on to step 10:
If we divide 810 by 91, we get 8 and a remainder of 82.
Put 8 as the next digit of the answer. 
Result so far: 862744.98
Subtract 728 from 810 to get 82.
Since there are no more digits in the dividend, we add a zero to the remainder making it 820, and continue the process.

Step 11:
If we divide 820 by 91, we get 9 and a remainder of 1.
Put 9 as the next digit of the answer. 
Result so far: 862744.989
Deduct 819 from 820 and we're left with 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Going ahead to step 12:
91 can be fit into 10 0 times, resulting in a remainder of 10.
Write down 0 as next digit of the result. 
Result so far: 862744.989
Subtract 0 from 10 to get 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Going ahead to step 13:
91 can be fit into 100 1 times, resulting in a remainder of 9.
Use 1 as the next digit of our solution. 
Result so far: 862744.98901
If we subtract 91 from 100, we get 9.
Since there are no more digits in the dividend, we add a zero to the remainder making it 90, and continue the process.

On to step 14:
If we divide 90 by 91, we get 0 and a remainder of 90.
Put 0 as the next digit of the answer. 
Result so far: 862744.98901
If we subtract 0 from 90, we get 90.
Since there are no more digits in the dividend, we add a zero to the remainder making it 900, and continue the process.

Moving on to step 15:
The number 91 fits into 900 9 times, leaving a remainder of 81.
Put 9 as the next digit of the answer. 
Result so far: 862744.9890109
Subtract 819 from 900 to get 81.
Since there are no more digits in the dividend, we add a zero to the remainder making it 810, and continue the process.

Let's proceed to step 16:
If we divide 810 by 91, we get 8 and a remainder of 82.
Use 8 as the next digit of our solution. 
Result so far: 862744.98901098
If we take 728 away from 810, we end up with 82.
Since there are no more digits in the dividend, we add a zero to the remainder making it 820, and continue the process.

Our division results in 862744.98901098 with a remaining 8.2e-08.