51108309 ÷ 391 
The aim is to understand the frequency of 391 in 51108309.

Let's proceed to step 1:
5 divided by 391 is 0 with a remainder of 5.
Put 0 as the next digit of the answer. 
Result so far: 0.0
The remainder is 5 after subtracting 0 from 5.
Include the next digit (1) from the dividend after 5, then repeat: 51 / 391

Going ahead to step 2:
391 goes into 51 0 times with a remainder of 51.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Subtract 0 from 51 to get 51.
Bring next digit (1) of the dividend behind the 51 and repeat the process: 511 / 391

Let's proceed to step 3:
If we divide 511 by 391, we get 1 and a remainder of 120.
The number 1 becomes the next digit in our result. 
Result so far: 1.0
If we take 391 away from 511, we end up with 120.
Include the next digit (0) from the dividend after 120, then repeat: 1200 / 391

Let's proceed to step 4:
1200 divided by 391 is 3 with a remainder of 27.
Use 3 as the next digit of our solution. 
Result so far: 13.0
If we subtract 1173 from 1200, we get 27.
Fetch the next digit (8) from the dividend, attach it to 27 and continue: 278 / 391

Advancing to step 5:
When dividing 278 by 391, we get 0 with a remainder of 278.
The number 0 becomes the next digit in our result. 
Result so far: 130.0
Deduct 0 from 278 and we're left with 278.
Append the next digit (3) from the dividend to 278 and continue with: 2783 / 391

Advancing to step 6:
The number 391 fits into 2783 7 times, leaving a remainder of 46.
The next digit of our result is 7. 
Result so far: 1307.0
Deduct 2737 from 2783 and we're left with 46.
Fetch the next digit (0) from the dividend, attach it to 46 and continue: 460 / 391

On to step 7:
391 can be fit into 460 1 times, resulting in a remainder of 69.
Use 1 as the next digit of our solution. 
Result so far: 13071.0
If we subtract 391 from 460, we get 69.
Bring next digit (9) of the dividend behind the 69 and repeat the process: 699 / 391

Advancing to step 8:
391 can be fit into 699 1 times, resulting in a remainder of 308.
Use 1 as the next digit of our solution. 
Result so far: 130711.0
Subtracting 391 from 699 leaves us with 308.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3080, and continue the process.

Step 9:
The number 391 fits into 3080 7 times, leaving a remainder of 343.
Record the quotient 7 as the next digit in the result. 
Result so far: 130711.7
Deduct 2737 from 3080 and we're left with 343.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3430, and continue the process.

Step 10:
3430 divided by 391 is 8 with a remainder of 302.
Put 8 as the next digit of the answer. 
Result so far: 130711.78
Deduct 3128 from 3430 and we're left with 302.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3020, and continue the process.

Step 11:
If we divide 3020 by 391, we get 7 and a remainder of 283.
Record the quotient 7 as the next digit in the result. 
Result so far: 130711.787
Deduct 2737 from 3020 and we're left with 283.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2830, and continue the process.

Going ahead to step 12:
391 goes into 2830 7 times with a remainder of 93.
The next digit of our result is 7. 
Result so far: 130711.7877
Subtracting 2737 from 2830 leaves us with 93.
Since there are no more digits in the dividend, we add a zero to the remainder making it 930, and continue the process.

The quotient of the division is 130711.7877, and the remainder is 0.00093.