We divide 79980502 by 991
The aim is to understand the frequency of 991 in 79980502.

Going ahead to step 1:
991 can be fit into 7 0 times, resulting in a remainder of 7.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Deduct 0 from 7 and we're left with 7.
Append the next digit (9) from the dividend to 7 and continue with: 79 / 991

Moving on to step 2:
79 divided by 991 is 0 with a remainder of 79.
Use 0 as the next digit of our solution. 
Result so far: 0.0
If we subtract 0 from 79, we get 79.
Grab the next digit (9) from the dividend, add it to 79, then carry on: 799 / 991

Let's proceed to step 3:
The number 991 fits into 799 0 times, leaving a remainder of 799.
The next digit of our result is 0. 
Result so far: 0.0
Deduct 0 from 799 and we're left with 799.
Bring next digit (8) of the dividend behind the 799 and repeat the process: 7998 / 991

Going ahead to step 4:
991 can be fit into 7998 8 times, resulting in a remainder of 70.
Put 8 as the next digit of the answer. 
Result so far: 8.0
Subtract 7928 from 7998 to get 70.
Grab the next digit (0) from the dividend, add it to 70, then carry on: 700 / 991

Step 5:
991 goes into 700 0 times with a remainder of 700.
Put 0 as the next digit of the answer. 
Result so far: 80.0
If we take 0 away from 700, we end up with 700.
Bring next digit (5) of the dividend behind the 700 and repeat the process: 7005 / 991

Going ahead to step 6:
7005 divided by 991 is 7 with a remainder of 68.
Record the quotient 7 as the next digit in the result. 
Result so far: 807.0
Subtract 6937 from 7005 to get 68.
Fetch the next digit (0) from the dividend, attach it to 68 and continue: 680 / 991

Moving on to step 7:
991 goes into 680 0 times with a remainder of 680.
Put 0 as the next digit of the answer. 
Result so far: 8070.0
Subtracting 0 from 680 leaves us with 680.
Take the next digit (2) from the dividend and append it to 680, then repeat: 6802 / 991

Moving on to step 8:
When dividing 6802 by 991, we get 6 with a remainder of 856.
Record the quotient 6 as the next digit in the result. 
Result so far: 80706.0
The remainder is 856 after subtracting 5946 from 6802.
Since there are no more digits in the dividend, we add a zero to the remainder making it 8560, and continue the process.

Going ahead to step 9:
The number 991 fits into 8560 8 times, leaving a remainder of 632.
Put 8 as the next digit of the answer. 
Result so far: 80706.8
The remainder is 632 after subtracting 7928 from 8560.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6320, and continue the process.

Step 10:
991 goes into 6320 6 times with a remainder of 374.
Write down 6 as next digit of the result. 
Result so far: 80706.86
Deduct 5946 from 6320 and we're left with 374.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3740, and continue the process.

Moving on to step 11:
When dividing 3740 by 991, we get 3 with a remainder of 767.
Use 3 as the next digit of our solution. 
Result so far: 80706.863
Subtract 2973 from 3740 to get 767.
Since there are no more digits in the dividend, we add a zero to the remainder making it 7670, and continue the process.

Moving on to step 12:
The number 991 fits into 7670 7 times, leaving a remainder of 733.
Write down 7 as next digit of the result. 
Result so far: 80706.8637
If we subtract 6937 from 7670, we get 733.
Since there are no more digits in the dividend, we add a zero to the remainder making it 7330, and continue the process.

On to step 13:
When dividing 7330 by 991, we get 7 with a remainder of 393.
The number 7 becomes the next digit in our result. 
Result so far: 80706.86377
If we subtract 6937 from 7330, we get 393.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3930, and continue the process.

After the division, we end up with 80706.86377 and a remainder of 0.000393.