We look at the division of 81836275 by 561 
The aim is to understand the frequency of 561 in 81836275.

Let's proceed to step 1:
The number 561 fits into 8 0 times, leaving a remainder of 8.
Write down 0 as next digit of the result. 
Result so far: 0.0
Deduct 0 from 8 and we're left with 8.
Take the next digit (1) from the dividend and append it to 8, then repeat: 81 / 561

Advancing to step 2:
561 can be fit into 81 0 times, resulting in a remainder of 81.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
The remainder is 81 after subtracting 0 from 81.
Bring next digit (8) of the dividend behind the 81 and repeat the process: 818 / 561

Advancing to step 3:
When dividing 818 by 561, we get 1 with a remainder of 257.
The number 1 becomes the next digit in our result. 
Result so far: 1.0
The remainder is 257 after subtracting 561 from 818.
Take the next digit (3) from the dividend and append it to 257, then repeat: 2573 / 561

Let's proceed to step 4:
When dividing 2573 by 561, we get 4 with a remainder of 329.
Use 4 as the next digit of our solution. 
Result so far: 14.0
The remainder is 329 after subtracting 2244 from 2573.
Grab the next digit (6) from the dividend, add it to 329, then carry on: 3296 / 561

Step 5:
561 can be fit into 3296 5 times, resulting in a remainder of 491.
Put 5 as the next digit of the answer. 
Result so far: 145.0
Subtracting 2805 from 3296 leaves us with 491.
Bring next digit (2) of the dividend behind the 491 and repeat the process: 4912 / 561

Let's proceed to step 6:
When dividing 4912 by 561, we get 8 with a remainder of 424.
Record the quotient 8 as the next digit in the result. 
Result so far: 1458.0
Subtract 4488 from 4912 to get 424.
Include the next digit (7) from the dividend after 424, then repeat: 4247 / 561

Advancing to step 7:
561 can be fit into 4247 7 times, resulting in a remainder of 320.
Put 7 as the next digit of the answer. 
Result so far: 14587.0
If we subtract 3927 from 4247, we get 320.
Bring next digit (5) of the dividend behind the 320 and repeat the process: 3205 / 561

Step 8:
When dividing 3205 by 561, we get 5 with a remainder of 400.
The number 5 becomes the next digit in our result. 
Result so far: 145875.0
Deduct 2805 from 3205 and we're left with 400.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4000, and continue the process.

On to step 9:
561 goes into 4000 7 times with a remainder of 73.
Record the quotient 7 as the next digit in the result. 
Result so far: 145875.7
Subtract 3927 from 4000 to get 73.
Since there are no more digits in the dividend, we add a zero to the remainder making it 730, and continue the process.

On to step 10:
561 goes into 730 1 times with a remainder of 169.
The number 1 becomes the next digit in our result. 
Result so far: 145875.71
Deduct 561 from 730 and we're left with 169.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1690, and continue the process.

Step 11:
1690 divided by 561 is 3 with a remainder of 7.
The number 3 becomes the next digit in our result. 
Result so far: 145875.713
If we take 1683 away from 1690, we end up with 7.
Since there are no more digits in the dividend, we add a zero to the remainder making it 70, and continue the process.

Step 12:
561 can be fit into 70 0 times, resulting in a remainder of 70.
Record the quotient 0 as the next digit in the result. 
Result so far: 145875.713
Subtracting 0 from 70 leaves us with 70.
Since there are no more digits in the dividend, we add a zero to the remainder making it 700, and continue the process.

Advancing to step 13:
561 goes into 700 1 times with a remainder of 139.
Write down 1 as next digit of the result. 
Result so far: 145875.71301
Subtract 561 from 700 to get 139.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1390, and continue the process.

Moving on to step 14:
If we divide 1390 by 561, we get 2 and a remainder of 268.
Use 2 as the next digit of our solution. 
Result so far: 145875.713012
The remainder is 268 after subtracting 1122 from 1390.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2680, and continue the process.

Let's proceed to step 15:
The number 561 fits into 2680 4 times, leaving a remainder of 436.
Record the quotient 4 as the next digit in the result. 
Result so far: 145875.7130124
Deduct 2244 from 2680 and we're left with 436.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4360, and continue the process.

On to step 16:
If we divide 4360 by 561, we get 7 and a remainder of 433.
The number 7 becomes the next digit in our result. 
Result so far: 145875.71301247
The remainder is 433 after subtracting 3927 from 4360.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4330, and continue the process.

The final outcome is 145875.71301247, with a leftover of 4.33e-07.