811431 ÷ 521 
The aim is to understand the frequency of 521 in 811431.

Moving on to step 1:
521 can be fit into 8 0 times, resulting in a remainder of 8.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Deduct 0 from 8 and we're left with 8.
Fetch the next digit (1) from the dividend, attach it to 8 and continue: 81 / 521

Going ahead to step 2:
521 goes into 81 0 times with a remainder of 81.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtract 0 from 81 to get 81.
Grab the next digit (1) from the dividend, add it to 81, then carry on: 811 / 521

Moving on to step 3:
811 divided by 521 is 1 with a remainder of 290.
Use 1 as the next digit of our solution. 
Result so far: 1.0
If we take 521 away from 811, we end up with 290.
Append the next digit (4) from the dividend to 290 and continue with: 2904 / 521

Advancing to step 4:
521 goes into 2904 5 times with a remainder of 299.
Write down 5 as next digit of the result. 
Result so far: 15.0
Deduct 2605 from 2904 and we're left with 299.
Bring next digit (3) of the dividend behind the 299 and repeat the process: 2993 / 521

Advancing to step 5:
521 can be fit into 2993 5 times, resulting in a remainder of 388.
Use 5 as the next digit of our solution. 
Result so far: 155.0
Subtract 2605 from 2993 to get 388.
Grab the next digit (1) from the dividend, add it to 388, then carry on: 3881 / 521

Going ahead to step 6:
521 goes into 3881 7 times with a remainder of 234.
The number 7 becomes the next digit in our result. 
Result so far: 1557.0
If we take 3647 away from 3881, we end up with 234.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2340, and continue the process.

Moving on to step 7:
The number 521 fits into 2340 4 times, leaving a remainder of 256.
The next digit of our result is 4. 
Result so far: 1557.4
Subtract 2084 from 2340 to get 256.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2560, and continue the process.

On to step 8:
If we divide 2560 by 521, we get 4 and a remainder of 476.
Record the quotient 4 as the next digit in the result. 
Result so far: 1557.44
Subtracting 2084 from 2560 leaves us with 476.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4760, and continue the process.

After the division, we end up with 1557.44 and a remainder of 0.476.