86977047 ÷ 521 
The aim is to understand the frequency of 521 in 86977047.

Let's proceed to step 1:
521 goes into 8 0 times with a remainder of 8.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtracting 0 from 8 leaves us with 8.
Grab the next digit (6) from the dividend, add it to 8, then carry on: 86 / 521

Moving on to step 2:
The number 521 fits into 86 0 times, leaving a remainder of 86.
The next digit of our result is 0. 
Result so far: 0.0
Subtracting 0 from 86 leaves us with 86.
Grab the next digit (9) from the dividend, add it to 86, then carry on: 869 / 521

Advancing to step 3:
869 divided by 521 is 1 with a remainder of 348.
Write down 1 as next digit of the result. 
Result so far: 1.0
The remainder is 348 after subtracting 521 from 869.
Fetch the next digit (7) from the dividend, attach it to 348 and continue: 3487 / 521

Advancing to step 4:
When dividing 3487 by 521, we get 6 with a remainder of 361.
The number 6 becomes the next digit in our result. 
Result so far: 16.0
If we take 3126 away from 3487, we end up with 361.
Take the next digit (7) from the dividend and append it to 361, then repeat: 3617 / 521

On to step 5:
3617 divided by 521 is 6 with a remainder of 491.
Use 6 as the next digit of our solution. 
Result so far: 166.0
If we subtract 3126 from 3617, we get 491.
Include the next digit (0) from the dividend after 491, then repeat: 4910 / 521

Going ahead to step 6:
4910 divided by 521 is 9 with a remainder of 221.
The number 9 becomes the next digit in our result. 
Result so far: 1669.0
If we take 4689 away from 4910, we end up with 221.
Bring next digit (4) of the dividend behind the 221 and repeat the process: 2214 / 521

On to step 7:
The number 521 fits into 2214 4 times, leaving a remainder of 130.
Write down 4 as next digit of the result. 
Result so far: 16694.0
If we take 2084 away from 2214, we end up with 130.
Append the next digit (7) from the dividend to 130 and continue with: 1307 / 521

On to step 8:
1307 divided by 521 is 2 with a remainder of 265.
Record the quotient 2 as the next digit in the result. 
Result so far: 166942.0
Subtracting 1042 from 1307 leaves us with 265.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2650, and continue the process.

Let's proceed to step 9:
If we divide 2650 by 521, we get 5 and a remainder of 45.
Record the quotient 5 as the next digit in the result. 
Result so far: 166942.5
If we subtract 2605 from 2650, we get 45.
Since there are no more digits in the dividend, we add a zero to the remainder making it 450, and continue the process.

Let's proceed to step 10:
521 can be fit into 450 0 times, resulting in a remainder of 450.
Use 0 as the next digit of our solution. 
Result so far: 166942.5
The remainder is 450 after subtracting 0 from 450.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4500, and continue the process.

Advancing to step 11:
When dividing 4500 by 521, we get 8 with a remainder of 332.
Write down 8 as next digit of the result. 
Result so far: 166942.508
Subtracting 4168 from 4500 leaves us with 332.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3320, and continue the process.

Let's proceed to step 12:
When dividing 3320 by 521, we get 6 with a remainder of 194.
Put 6 as the next digit of the answer. 
Result so far: 166942.5086
If we take 3126 away from 3320, we end up with 194.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1940, and continue the process.

Step 13:
1940 divided by 521 is 3 with a remainder of 377.
Write down 3 as next digit of the result. 
Result so far: 166942.50863
Subtracting 1563 from 1940 leaves us with 377.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3770, and continue the process.

On to step 14:
The number 521 fits into 3770 7 times, leaving a remainder of 123.
Record the quotient 7 as the next digit in the result. 
Result so far: 166942.508637
Subtract 3647 from 3770 to get 123.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1230, and continue the process.

Step 15:
521 goes into 1230 2 times with a remainder of 188.
Use 2 as the next digit of our solution. 
Result so far: 166942.5086372
Subtracting 1042 from 1230 leaves us with 188.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1880, and continue the process.

On to step 16:
521 can be fit into 1880 3 times, resulting in a remainder of 317.
Write down 3 as next digit of the result. 
Result so far: 166942.50863723
Subtract 1563 from 1880 to get 317.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3170, and continue the process.

The final result is 166942.50863723 with a remainder of 3.17e-07.