25602 divided by 81 
The aim is to understand the frequency of 81 in 25602.

Advancing to step 1:
2 divided by 81 is 0 with a remainder of 2.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtract 0 from 2 to get 2.
Bring next digit (5) of the dividend behind the 2 and repeat the process: 25 / 81

Advancing to step 2:
The number 81 fits into 25 0 times, leaving a remainder of 25.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Subtract 0 from 25 to get 25.
Take the next digit (6) from the dividend and append it to 25, then repeat: 256 / 81

On to step 3:
If we divide 256 by 81, we get 3 and a remainder of 13.
Use 3 as the next digit of our solution. 
Result so far: 3.0
Subtracting 243 from 256 leaves us with 13.
Grab the next digit (0) from the dividend, add it to 13, then carry on: 130 / 81

On to step 4:
The number 81 fits into 130 1 times, leaving a remainder of 49.
Put 1 as the next digit of the answer. 
Result so far: 31.0
The remainder is 49 after subtracting 81 from 130.
Bring next digit (2) of the dividend behind the 49 and repeat the process: 492 / 81

Step 5:
If we divide 492 by 81, we get 6 and a remainder of 6.
Write down 6 as next digit of the result. 
Result so far: 316.0
Subtracting 486 from 492 leaves us with 6.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

Advancing to step 6:
60 divided by 81 is 0 with a remainder of 60.
Write down 0 as next digit of the result. 
Result so far: 316.0
If we subtract 0 from 60, we get 60.
Since there are no more digits in the dividend, we add a zero to the remainder making it 600, and continue the process.

On to step 7:
The number 81 fits into 600 7 times, leaving a remainder of 33.
Use 7 as the next digit of our solution. 
Result so far: 316.07
The remainder is 33 after subtracting 567 from 600.
Since there are no more digits in the dividend, we add a zero to the remainder making it 330, and continue the process.

Let's proceed to step 8:
The number 81 fits into 330 4 times, leaving a remainder of 6.
The next digit of our result is 4. 
Result so far: 316.074
The remainder is 6 after subtracting 324 from 330.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

Step 9:
The number 81 fits into 60 0 times, leaving a remainder of 60.
The number 0 becomes the next digit in our result. 
Result so far: 316.074
If we subtract 0 from 60, we get 60.
Since there are no more digits in the dividend, we add a zero to the remainder making it 600, and continue the process.

On to step 10:
If we divide 600 by 81, we get 7 and a remainder of 33.
The number 7 becomes the next digit in our result. 
Result so far: 316.07407
The remainder is 33 after subtracting 567 from 600.
Since there are no more digits in the dividend, we add a zero to the remainder making it 330, and continue the process.

Going ahead to step 11:
The number 81 fits into 330 4 times, leaving a remainder of 6.
Put 4 as the next digit of the answer. 
Result so far: 316.074074
If we subtract 324 from 330, we get 6.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

Moving on to step 12:
If we divide 60 by 81, we get 0 and a remainder of 60.
The next digit of our result is 0. 
Result so far: 316.074074
The remainder is 60 after subtracting 0 from 60.
Since there are no more digits in the dividend, we add a zero to the remainder making it 600, and continue the process.

Let's proceed to step 13:
81 can be fit into 600 7 times, resulting in a remainder of 33.
The next digit of our result is 7. 
Result so far: 316.07407407
Subtracting 567 from 600 leaves us with 33.
Since there are no more digits in the dividend, we add a zero to the remainder making it 330, and continue the process.

The quotient of the division is 316.07407407, and the remainder is 3.3e-08.