We look at the division of 16538413 by 803 
The aim is to understand the frequency of 803 in 16538413.

Step 1:
The number 803 fits into 1 0 times, leaving a remainder of 1.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Subtracting 0 from 1 leaves us with 1.
Fetch the next digit (6) from the dividend, attach it to 1 and continue: 16 / 803

Moving on to step 2:
16 divided by 803 is 0 with a remainder of 16.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we subtract 0 from 16, we get 16.
Grab the next digit (5) from the dividend, add it to 16, then carry on: 165 / 803

Let's proceed to step 3:
803 goes into 165 0 times with a remainder of 165.
Write down 0 as next digit of the result. 
Result so far: 0.0
If we take 0 away from 165, we end up with 165.
Include the next digit (3) from the dividend after 165, then repeat: 1653 / 803

On to step 4:
If we divide 1653 by 803, we get 2 and a remainder of 47.
The next digit of our result is 2. 
Result so far: 2.0
The remainder is 47 after subtracting 1606 from 1653.
Bring next digit (8) of the dividend behind the 47 and repeat the process: 478 / 803

Moving on to step 5:
When dividing 478 by 803, we get 0 with a remainder of 478.
Write down 0 as next digit of the result. 
Result so far: 20.0
Subtract 0 from 478 to get 478.
Fetch the next digit (4) from the dividend, attach it to 478 and continue: 4784 / 803

On to step 6:
4784 divided by 803 is 5 with a remainder of 769.
The next digit of our result is 5. 
Result so far: 205.0
Deduct 4015 from 4784 and we're left with 769.
Take the next digit (1) from the dividend and append it to 769, then repeat: 7691 / 803

Going ahead to step 7:
If we divide 7691 by 803, we get 9 and a remainder of 464.
The next digit of our result is 9. 
Result so far: 2059.0
Subtracting 7227 from 7691 leaves us with 464.
Include the next digit (3) from the dividend after 464, then repeat: 4643 / 803

Let's proceed to step 8:
4643 divided by 803 is 5 with a remainder of 628.
The number 5 becomes the next digit in our result. 
Result so far: 20595.0
Deduct 4015 from 4643 and we're left with 628.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6280, and continue the process.

Advancing to step 9:
803 goes into 6280 7 times with a remainder of 659.
Use 7 as the next digit of our solution. 
Result so far: 20595.7
Deduct 5621 from 6280 and we're left with 659.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6590, and continue the process.

Step 10:
When dividing 6590 by 803, we get 8 with a remainder of 166.
The next digit of our result is 8. 
Result so far: 20595.78
The remainder is 166 after subtracting 6424 from 6590.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1660, and continue the process.

Advancing to step 11:
803 goes into 1660 2 times with a remainder of 54.
The number 2 becomes the next digit in our result. 
Result so far: 20595.782
Subtract 1606 from 1660 to get 54.
Since there are no more digits in the dividend, we add a zero to the remainder making it 540, and continue the process.

Going ahead to step 12:
803 can be fit into 540 0 times, resulting in a remainder of 540.
Put 0 as the next digit of the answer. 
Result so far: 20595.782
If we take 0 away from 540, we end up with 540.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5400, and continue the process.

Let's proceed to step 13:
When dividing 5400 by 803, we get 6 with a remainder of 582.
The next digit of our result is 6. 
Result so far: 20595.78206
The remainder is 582 after subtracting 4818 from 5400.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5820, and continue the process.

Advancing to step 14:
803 goes into 5820 7 times with a remainder of 199.
Use 7 as the next digit of our solution. 
Result so far: 20595.782067
If we take 5621 away from 5820, we end up with 199.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1990, and continue the process.

Advancing to step 15:
803 can be fit into 1990 2 times, resulting in a remainder of 384.
Use 2 as the next digit of our solution. 
Result so far: 20595.7820672
The remainder is 384 after subtracting 1606 from 1990.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3840, and continue the process.

Going ahead to step 16:
803 can be fit into 3840 4 times, resulting in a remainder of 628.
Put 4 as the next digit of the answer. 
Result so far: 20595.78206724
The remainder is 628 after subtracting 3212 from 3840.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6280, and continue the process.

After the division, we end up with 20595.78206724 and a remainder of 6.28e-07.