We're dividing 86991359 by 556 
The aim is to understand the frequency of 556 in 86991359.

Advancing to step 1:
The number 556 fits into 8 0 times, leaving a remainder of 8.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we subtract 0 from 8, we get 8.
Append the next digit (6) from the dividend to 8 and continue with: 86 / 556

On to step 2:
When dividing 86 by 556, we get 0 with a remainder of 86.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we subtract 0 from 86, we get 86.
Take the next digit (9) from the dividend and append it to 86, then repeat: 869 / 556

Going ahead to step 3:
When dividing 869 by 556, we get 1 with a remainder of 313.
Write down 1 as next digit of the result. 
Result so far: 1.0
If we subtract 556 from 869, we get 313.
Bring next digit (9) of the dividend behind the 313 and repeat the process: 3139 / 556

Going ahead to step 4:
556 goes into 3139 5 times with a remainder of 359.
Use 5 as the next digit of our solution. 
Result so far: 15.0
Subtracting 2780 from 3139 leaves us with 359.
Bring next digit (1) of the dividend behind the 359 and repeat the process: 3591 / 556

Going ahead to step 5:
The number 556 fits into 3591 6 times, leaving a remainder of 255.
Put 6 as the next digit of the answer. 
Result so far: 156.0
Subtract 3336 from 3591 to get 255.
Include the next digit (3) from the dividend after 255, then repeat: 2553 / 556

Moving on to step 6:
556 can be fit into 2553 4 times, resulting in a remainder of 329.
Use 4 as the next digit of our solution. 
Result so far: 1564.0
Deduct 2224 from 2553 and we're left with 329.
Bring next digit (5) of the dividend behind the 329 and repeat the process: 3295 / 556

Step 7:
When dividing 3295 by 556, we get 5 with a remainder of 515.
Put 5 as the next digit of the answer. 
Result so far: 15645.0
Deduct 2780 from 3295 and we're left with 515.
Grab the next digit (9) from the dividend, add it to 515, then carry on: 5159 / 556

Going ahead to step 8:
The number 556 fits into 5159 9 times, leaving a remainder of 155.
Put 9 as the next digit of the answer. 
Result so far: 156459.0
Subtract 5004 from 5159 to get 155.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1550, and continue the process.

Moving on to step 9:
The number 556 fits into 1550 2 times, leaving a remainder of 438.
Put 2 as the next digit of the answer. 
Result so far: 156459.2
Deduct 1112 from 1550 and we're left with 438.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4380, and continue the process.

Going ahead to step 10:
The number 556 fits into 4380 7 times, leaving a remainder of 488.
Write down 7 as next digit of the result. 
Result so far: 156459.27
If we subtract 3892 from 4380, we get 488.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4880, and continue the process.

Moving on to step 11:
4880 divided by 556 is 8 with a remainder of 432.
The next digit of our result is 8. 
Result so far: 156459.278
If we subtract 4448 from 4880, we get 432.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4320, and continue the process.

Moving on to step 12:
When dividing 4320 by 556, we get 7 with a remainder of 428.
Put 7 as the next digit of the answer. 
Result so far: 156459.2787
Subtracting 3892 from 4320 leaves us with 428.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4280, and continue the process.

Moving on to step 13:
When dividing 4280 by 556, we get 7 with a remainder of 388.
Put 7 as the next digit of the answer. 
Result so far: 156459.27877
Subtracting 3892 from 4280 leaves us with 388.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3880, and continue the process.

The final result is 156459.27877 with a remainder of 0.000388.