21595553 ÷ 425 
The aim is to understand the frequency of 425 in 21595553.

Advancing to step 1:
2 divided by 425 is 0 with a remainder of 2.
Write down 0 as next digit of the result. 
Result so far: 0.0
Subtract 0 from 2 to get 2.
Bring next digit (1) of the dividend behind the 2 and repeat the process: 21 / 425

Going ahead to step 2:
If we divide 21 by 425, we get 0 and a remainder of 21.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Subtracting 0 from 21 leaves us with 21.
Grab the next digit (5) from the dividend, add it to 21, then carry on: 215 / 425

On to step 3:
When dividing 215 by 425, we get 0 with a remainder of 215.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Subtract 0 from 215 to get 215.
Bring next digit (9) of the dividend behind the 215 and repeat the process: 2159 / 425

Advancing to step 4:
425 can be fit into 2159 5 times, resulting in a remainder of 34.
The next digit of our result is 5. 
Result so far: 5.0
Deduct 2125 from 2159 and we're left with 34.
Grab the next digit (5) from the dividend, add it to 34, then carry on: 345 / 425

Moving on to step 5:
When dividing 345 by 425, we get 0 with a remainder of 345.
Put 0 as the next digit of the answer. 
Result so far: 50.0
Subtracting 0 from 345 leaves us with 345.
Grab the next digit (5) from the dividend, add it to 345, then carry on: 3455 / 425

Advancing to step 6:
425 can be fit into 3455 8 times, resulting in a remainder of 55.
Record the quotient 8 as the next digit in the result. 
Result so far: 508.0
Deduct 3400 from 3455 and we're left with 55.
Include the next digit (5) from the dividend after 55, then repeat: 555 / 425

On to step 7:
The number 425 fits into 555 1 times, leaving a remainder of 130.
The next digit of our result is 1. 
Result so far: 5081.0
Subtract 425 from 555 to get 130.
Append the next digit (3) from the dividend to 130 and continue with: 1303 / 425

Let's proceed to step 8:
425 can be fit into 1303 3 times, resulting in a remainder of 28.
Put 3 as the next digit of the answer. 
Result so far: 50813.0
The remainder is 28 after subtracting 1275 from 1303.
Since there are no more digits in the dividend, we add a zero to the remainder making it 280, and continue the process.

Let's proceed to step 9:
When dividing 280 by 425, we get 0 with a remainder of 280.
Put 0 as the next digit of the answer. 
Result so far: 50813.0
Deduct 0 from 280 and we're left with 280.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2800, and continue the process.

Step 10:
2800 divided by 425 is 6 with a remainder of 250.
Use 6 as the next digit of our solution. 
Result so far: 50813.06
If we take 2550 away from 2800, we end up with 250.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2500, and continue the process.

Going ahead to step 11:
When dividing 2500 by 425, we get 5 with a remainder of 375.
The number 5 becomes the next digit in our result. 
Result so far: 50813.065
Deduct 2125 from 2500 and we're left with 375.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3750, and continue the process.

Advancing to step 12:
When dividing 3750 by 425, we get 8 with a remainder of 350.
Write down 8 as next digit of the result. 
Result so far: 50813.0658
If we take 3400 away from 3750, we end up with 350.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3500, and continue the process.

Step 13:
The number 425 fits into 3500 8 times, leaving a remainder of 100.
Write down 8 as next digit of the result. 
Result so far: 50813.06588
Subtract 3400 from 3500 to get 100.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1000, and continue the process.

After the division, we end up with 50813.06588 and a remainder of 0.0001.