21599988 divided by 396 
The aim is to understand the frequency of 396 in 21599988.

Advancing to step 1:
If we divide 2 by 396, we get 0 and a remainder of 2.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we take 0 away from 2, we end up with 2.
Take the next digit (1) from the dividend and append it to 2, then repeat: 21 / 396

Let's proceed to step 2:
396 can be fit into 21 0 times, resulting in a remainder of 21.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
The remainder is 21 after subtracting 0 from 21.
Append the next digit (5) from the dividend to 21 and continue with: 215 / 396

Step 3:
The number 396 fits into 215 0 times, leaving a remainder of 215.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
If we subtract 0 from 215, we get 215.
Bring next digit (9) of the dividend behind the 215 and repeat the process: 2159 / 396

On to step 4:
The number 396 fits into 2159 5 times, leaving a remainder of 179.
Write down 5 as next digit of the result. 
Result so far: 5.0
Subtract 1980 from 2159 to get 179.
Grab the next digit (9) from the dividend, add it to 179, then carry on: 1799 / 396

Moving on to step 5:
If we divide 1799 by 396, we get 4 and a remainder of 215.
Record the quotient 4 as the next digit in the result. 
Result so far: 54.0
Deduct 1584 from 1799 and we're left with 215.
Grab the next digit (9) from the dividend, add it to 215, then carry on: 2159 / 396

Going ahead to step 6:
396 can be fit into 2159 5 times, resulting in a remainder of 179.
Write down 5 as next digit of the result. 
Result so far: 545.0
Deduct 1980 from 2159 and we're left with 179.
Take the next digit (8) from the dividend and append it to 179, then repeat: 1798 / 396

On to step 7:
When dividing 1798 by 396, we get 4 with a remainder of 214.
Use 4 as the next digit of our solution. 
Result so far: 5454.0
Subtract 1584 from 1798 to get 214.
Fetch the next digit (8) from the dividend, attach it to 214 and continue: 2148 / 396

On to step 8:
396 goes into 2148 5 times with a remainder of 168.
Record the quotient 5 as the next digit in the result. 
Result so far: 54545.0
Subtract 1980 from 2148 to get 168.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1680, and continue the process.

Let's proceed to step 9:
1680 divided by 396 is 4 with a remainder of 96.
Write down 4 as next digit of the result. 
Result so far: 54545.4
If we take 1584 away from 1680, we end up with 96.
Since there are no more digits in the dividend, we add a zero to the remainder making it 960, and continue the process.

Let's proceed to step 10:
The number 396 fits into 960 2 times, leaving a remainder of 168.
Write down 2 as next digit of the result. 
Result so far: 54545.42
If we take 792 away from 960, we end up with 168.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1680, and continue the process.

Advancing to step 11:
The number 396 fits into 1680 4 times, leaving a remainder of 96.
The number 4 becomes the next digit in our result. 
Result so far: 54545.424
Deduct 1584 from 1680 and we're left with 96.
Since there are no more digits in the dividend, we add a zero to the remainder making it 960, and continue the process.

Let's proceed to step 12:
When dividing 960 by 396, we get 2 with a remainder of 168.
Put 2 as the next digit of the answer. 
Result so far: 54545.4242
If we take 792 away from 960, we end up with 168.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1680, and continue the process.

Step 13:
396 can be fit into 1680 4 times, resulting in a remainder of 96.
Use 4 as the next digit of our solution. 
Result so far: 54545.42424
Subtract 1584 from 1680 to get 96.
Since there are no more digits in the dividend, we add a zero to the remainder making it 960, and continue the process.

Going ahead to step 14:
396 goes into 960 2 times with a remainder of 168.
Put 2 as the next digit of the answer. 
Result so far: 54545.424242
Deduct 792 from 960 and we're left with 168.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1680, and continue the process.

Advancing to step 15:
396 goes into 1680 4 times with a remainder of 96.
The next digit of our result is 4. 
Result so far: 54545.4242424
Subtracting 1584 from 1680 leaves us with 96.
Since there are no more digits in the dividend, we add a zero to the remainder making it 960, and continue the process.

Going ahead to step 16:
If we divide 960 by 396, we get 2 and a remainder of 168.
Put 2 as the next digit of the answer. 
Result so far: 54545.42424242
If we subtract 792 from 960, we get 168.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1680, and continue the process.

After the division, we end up with 54545.42424242 and a remainder of 1.68e-07.