51895478 ÷ 991 
The aim is to understand the frequency of 991 in 51895478.

Advancing to step 1:
When dividing 5 by 991, we get 0 with a remainder of 5.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
The remainder is 5 after subtracting 0 from 5.
Take the next digit (1) from the dividend and append it to 5, then repeat: 51 / 991

Going ahead to step 2:
51 divided by 991 is 0 with a remainder of 51.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Deduct 0 from 51 and we're left with 51.
Fetch the next digit (8) from the dividend, attach it to 51 and continue: 518 / 991

Going ahead to step 3:
991 goes into 518 0 times with a remainder of 518.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Subtracting 0 from 518 leaves us with 518.
Include the next digit (9) from the dividend after 518, then repeat: 5189 / 991

Moving on to step 4:
991 can be fit into 5189 5 times, resulting in a remainder of 234.
Write down 5 as next digit of the result. 
Result so far: 5.0
If we subtract 4955 from 5189, we get 234.
Append the next digit (5) from the dividend to 234 and continue with: 2345 / 991

Advancing to step 5:
2345 divided by 991 is 2 with a remainder of 363.
The number 2 becomes the next digit in our result. 
Result so far: 52.0
If we subtract 1982 from 2345, we get 363.
Include the next digit (4) from the dividend after 363, then repeat: 3634 / 991

Moving on to step 6:
If we divide 3634 by 991, we get 3 and a remainder of 661.
The next digit of our result is 3. 
Result so far: 523.0
The remainder is 661 after subtracting 2973 from 3634.
Include the next digit (7) from the dividend after 661, then repeat: 6617 / 991

Advancing to step 7:
The number 991 fits into 6617 6 times, leaving a remainder of 671.
Record the quotient 6 as the next digit in the result. 
Result so far: 5236.0
Deduct 5946 from 6617 and we're left with 671.
Take the next digit (8) from the dividend and append it to 671, then repeat: 6718 / 991

Moving on to step 8:
991 can be fit into 6718 6 times, resulting in a remainder of 772.
Write down 6 as next digit of the result. 
Result so far: 52366.0
Deduct 5946 from 6718 and we're left with 772.
Since there are no more digits in the dividend, we add a zero to the remainder making it 7720, and continue the process.

Step 9:
991 can be fit into 7720 7 times, resulting in a remainder of 783.
Use 7 as the next digit of our solution. 
Result so far: 52366.7
Deduct 6937 from 7720 and we're left with 783.
Since there are no more digits in the dividend, we add a zero to the remainder making it 7830, and continue the process.

Moving on to step 10:
The number 991 fits into 7830 7 times, leaving a remainder of 893.
The next digit of our result is 7. 
Result so far: 52366.77
If we take 6937 away from 7830, we end up with 893.
Since there are no more digits in the dividend, we add a zero to the remainder making it 8930, and continue the process.

The final outcome is 52366.77, with a leftover of 0.893.