We're dividing 15891239 by 398 
The aim is to understand the frequency of 398 in 15891239.

On to step 1:
1 divided by 398 is 0 with a remainder of 1.
Use 0 as the next digit of our solution. 
Result so far: 0.0
If we take 0 away from 1, we end up with 1.
Fetch the next digit (5) from the dividend, attach it to 1 and continue: 15 / 398

Step 2:
When dividing 15 by 398, we get 0 with a remainder of 15.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we subtract 0 from 15, we get 15.
Take the next digit (8) from the dividend and append it to 15, then repeat: 158 / 398

Going ahead to step 3:
The number 398 fits into 158 0 times, leaving a remainder of 158.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtract 0 from 158 to get 158.
Include the next digit (9) from the dividend after 158, then repeat: 1589 / 398

Going ahead to step 4:
1589 divided by 398 is 3 with a remainder of 395.
Put 3 as the next digit of the answer. 
Result so far: 3.0
Subtracting 1194 from 1589 leaves us with 395.
Append the next digit (1) from the dividend to 395 and continue with: 3951 / 398

Advancing to step 5:
The number 398 fits into 3951 9 times, leaving a remainder of 369.
Use 9 as the next digit of our solution. 
Result so far: 39.0
The remainder is 369 after subtracting 3582 from 3951.
Bring next digit (2) of the dividend behind the 369 and repeat the process: 3692 / 398

Going ahead to step 6:
398 can be fit into 3692 9 times, resulting in a remainder of 110.
Use 9 as the next digit of our solution. 
Result so far: 399.0
If we subtract 3582 from 3692, we get 110.
Take the next digit (3) from the dividend and append it to 110, then repeat: 1103 / 398

Advancing to step 7:
When dividing 1103 by 398, we get 2 with a remainder of 307.
Put 2 as the next digit of the answer. 
Result so far: 3992.0
Subtract 796 from 1103 to get 307.
Include the next digit (9) from the dividend after 307, then repeat: 3079 / 398

On to step 8:
398 can be fit into 3079 7 times, resulting in a remainder of 293.
The number 7 becomes the next digit in our result. 
Result so far: 39927.0
If we subtract 2786 from 3079, we get 293.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2930, and continue the process.

Advancing to step 9:
398 can be fit into 2930 7 times, resulting in a remainder of 144.
Use 7 as the next digit of our solution. 
Result so far: 39927.7
If we subtract 2786 from 2930, we get 144.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1440, and continue the process.

Going ahead to step 10:
398 can be fit into 1440 3 times, resulting in a remainder of 246.
Record the quotient 3 as the next digit in the result. 
Result so far: 39927.73
If we take 1194 away from 1440, we end up with 246.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2460, and continue the process.

Step 11:
When dividing 2460 by 398, we get 6 with a remainder of 72.
Record the quotient 6 as the next digit in the result. 
Result so far: 39927.736
If we subtract 2388 from 2460, we get 72.
Since there are no more digits in the dividend, we add a zero to the remainder making it 720, and continue the process.

On to step 12:
398 goes into 720 1 times with a remainder of 322.
Put 1 as the next digit of the answer. 
Result so far: 39927.7361
If we take 398 away from 720, we end up with 322.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3220, and continue the process.

Let's proceed to step 13:
The number 398 fits into 3220 8 times, leaving a remainder of 36.
Put 8 as the next digit of the answer. 
Result so far: 39927.73618
If we subtract 3184 from 3220, we get 36.
Since there are no more digits in the dividend, we add a zero to the remainder making it 360, and continue the process.

Moving on to step 14:
398 goes into 360 0 times with a remainder of 360.
Record the quotient 0 as the next digit in the result. 
Result so far: 39927.73618
The remainder is 360 after subtracting 0 from 360.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3600, and continue the process.

Let's proceed to step 15:
3600 divided by 398 is 9 with a remainder of 18.
Record the quotient 9 as the next digit in the result. 
Result so far: 39927.7361809
Deduct 3582 from 3600 and we're left with 18.
Since there are no more digits in the dividend, we add a zero to the remainder making it 180, and continue the process.

Advancing to step 16:
398 can be fit into 180 0 times, resulting in a remainder of 180.
Use 0 as the next digit of our solution. 
Result so far: 39927.7361809
If we take 0 away from 180, we end up with 180.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1800, and continue the process.

After the division, we end up with 39927.7361809 and a remainder of 1.8e-07.