We're dividing 7518978 by 991 
The aim is to understand the frequency of 991 in 7518978.

On to step 1:
The number 991 fits into 7 0 times, leaving a remainder of 7.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
If we subtract 0 from 7, we get 7.
Append the next digit (5) from the dividend to 7 and continue with: 75 / 991

Step 2:
75 divided by 991 is 0 with a remainder of 75.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Subtract 0 from 75 to get 75.
Grab the next digit (1) from the dividend, add it to 75, then carry on: 751 / 991

Step 3:
991 can be fit into 751 0 times, resulting in a remainder of 751.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we take 0 away from 751, we end up with 751.
Bring next digit (8) of the dividend behind the 751 and repeat the process: 7518 / 991

Moving on to step 4:
When dividing 7518 by 991, we get 7 with a remainder of 581.
Write down 7 as next digit of the result. 
Result so far: 7.0
Deduct 6937 from 7518 and we're left with 581.
Bring next digit (9) of the dividend behind the 581 and repeat the process: 5819 / 991

On to step 5:
When dividing 5819 by 991, we get 5 with a remainder of 864.
The next digit of our result is 5. 
Result so far: 75.0
Subtract 4955 from 5819 to get 864.
Include the next digit (7) from the dividend after 864, then repeat: 8647 / 991

Moving on to step 6:
When dividing 8647 by 991, we get 8 with a remainder of 719.
Record the quotient 8 as the next digit in the result. 
Result so far: 758.0
If we subtract 7928 from 8647, we get 719.
Include the next digit (8) from the dividend after 719, then repeat: 7198 / 991

Going ahead to step 7:
The number 991 fits into 7198 7 times, leaving a remainder of 261.
The next digit of our result is 7. 
Result so far: 7587.0
The remainder is 261 after subtracting 6937 from 7198.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2610, and continue the process.

Moving on to step 8:
2610 divided by 991 is 2 with a remainder of 628.
The next digit of our result is 2. 
Result so far: 7587.2
Subtract 1982 from 2610 to get 628.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6280, and continue the process.

On to step 9:
The number 991 fits into 6280 6 times, leaving a remainder of 334.
The number 6 becomes the next digit in our result. 
Result so far: 7587.26
Subtracting 5946 from 6280 leaves us with 334.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3340, and continue the process.

Going ahead to step 10:
991 goes into 3340 3 times with a remainder of 367.
Put 3 as the next digit of the answer. 
Result so far: 7587.263
If we subtract 2973 from 3340, we get 367.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3670, and continue the process.

On to step 11:
If we divide 3670 by 991, we get 3 and a remainder of 697.
Record the quotient 3 as the next digit in the result. 
Result so far: 7587.2633
Subtract 2973 from 3670 to get 697.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6970, and continue the process.

In conclusion, the division gives 7587.2633 with a balance of 0.00697.