28221338 ÷ 399 
The aim is to understand the frequency of 399 in 28221338.

Advancing to step 1:
399 goes into 2 0 times with a remainder of 2.
The next digit of our result is 0. 
Result so far: 0.0
If we subtract 0 from 2, we get 2.
Include the next digit (8) from the dividend after 2, then repeat: 28 / 399

Moving on to step 2:
If we divide 28 by 399, we get 0 and a remainder of 28.
Write down 0 as next digit of the result. 
Result so far: 0.0
Deduct 0 from 28 and we're left with 28.
Grab the next digit (2) from the dividend, add it to 28, then carry on: 282 / 399

On to step 3:
399 can be fit into 282 0 times, resulting in a remainder of 282.
The next digit of our result is 0. 
Result so far: 0.0
Subtract 0 from 282 to get 282.
Take the next digit (2) from the dividend and append it to 282, then repeat: 2822 / 399

Let's proceed to step 4:
When dividing 2822 by 399, we get 7 with a remainder of 29.
Put 7 as the next digit of the answer. 
Result so far: 7.0
The remainder is 29 after subtracting 2793 from 2822.
Take the next digit (1) from the dividend and append it to 29, then repeat: 291 / 399

Advancing to step 5:
The number 399 fits into 291 0 times, leaving a remainder of 291.
Write down 0 as next digit of the result. 
Result so far: 70.0
If we take 0 away from 291, we end up with 291.
Append the next digit (3) from the dividend to 291 and continue with: 2913 / 399

Let's proceed to step 6:
When dividing 2913 by 399, we get 7 with a remainder of 120.
Use 7 as the next digit of our solution. 
Result so far: 707.0
The remainder is 120 after subtracting 2793 from 2913.
Include the next digit (3) from the dividend after 120, then repeat: 1203 / 399

On to step 7:
If we divide 1203 by 399, we get 3 and a remainder of 6.
Use 3 as the next digit of our solution. 
Result so far: 7073.0
Subtracting 1197 from 1203 leaves us with 6.
Append the next digit (8) from the dividend to 6 and continue with: 68 / 399

Moving on to step 8:
If we divide 68 by 399, we get 0 and a remainder of 68.
Use 0 as the next digit of our solution. 
Result so far: 70730.0
Deduct 0 from 68 and we're left with 68.
Since there are no more digits in the dividend, we add a zero to the remainder making it 680, and continue the process.

Going ahead to step 9:
The number 399 fits into 680 1 times, leaving a remainder of 281.
Record the quotient 1 as the next digit in the result. 
Result so far: 70730.1
If we subtract 399 from 680, we get 281.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2810, and continue the process.

Step 10:
When dividing 2810 by 399, we get 7 with a remainder of 17.
Record the quotient 7 as the next digit in the result. 
Result so far: 70730.17
Subtracting 2793 from 2810 leaves us with 17.
Since there are no more digits in the dividend, we add a zero to the remainder making it 170, and continue the process.

Let's proceed to step 11:
When dividing 170 by 399, we get 0 with a remainder of 170.
Put 0 as the next digit of the answer. 
Result so far: 70730.17
The remainder is 170 after subtracting 0 from 170.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1700, and continue the process.

On to step 12:
399 goes into 1700 4 times with a remainder of 104.
The number 4 becomes the next digit in our result. 
Result so far: 70730.1704
If we take 1596 away from 1700, we end up with 104.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1040, and continue the process.

On to step 13:
The number 399 fits into 1040 2 times, leaving a remainder of 242.
Use 2 as the next digit of our solution. 
Result so far: 70730.17042
The remainder is 242 after subtracting 798 from 1040.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2420, and continue the process.

Going ahead to step 14:
When dividing 2420 by 399, we get 6 with a remainder of 26.
The number 6 becomes the next digit in our result. 
Result so far: 70730.170426
Subtract 2394 from 2420 to get 26.
Since there are no more digits in the dividend, we add a zero to the remainder making it 260, and continue the process.

Advancing to step 15:
The number 399 fits into 260 0 times, leaving a remainder of 260.
The next digit of our result is 0. 
Result so far: 70730.170426
If we subtract 0 from 260, we get 260.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2600, and continue the process.

Going ahead to step 16:
399 goes into 2600 6 times with a remainder of 206.
The number 6 becomes the next digit in our result. 
Result so far: 70730.17042606
If we subtract 2394 from 2600, we get 206.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2060, and continue the process.

Our division results in 70730.17042606 with a remaining 2.06e-07.