We're dividing 16943381 by 321 
The aim is to understand the frequency of 321 in 16943381.

Step 1:
The number 321 fits into 1 0 times, leaving 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.
Append the next digit (6) from the dividend to 1 and continue with: 16 / 321

On to step 2:
321 can be fit into 16 0 times, resulting in a remainder of 16.
Write down 0 as next digit of the result. 
Result so far: 0.0
Subtract 0 from 16 to get 16.
Grab the next digit (9) from the dividend, add it to 16, then carry on: 169 / 321

Moving on to step 3:
When dividing 169 by 321, we get 0 with a remainder of 169.
Write down 0 as next digit of the result. 
Result so far: 0.0
If we subtract 0 from 169, we get 169.
Grab the next digit (4) from the dividend, add it to 169, then carry on: 1694 / 321

On to step 4:
1694 divided by 321 is 5 with a remainder of 89.
The number 5 becomes the next digit in our result. 
Result so far: 5.0
If we subtract 1605 from 1694, we get 89.
Append the next digit (3) from the dividend to 89 and continue with: 893 / 321

Step 5:
321 can be fit into 893 2 times, resulting in a remainder of 251.
Write down 2 as next digit of the result. 
Result so far: 52.0
Subtract 642 from 893 to get 251.
Append the next digit (3) from the dividend to 251 and continue with: 2513 / 321

On to step 6:
2513 divided by 321 is 7 with a remainder of 266.
Use 7 as the next digit of our solution. 
Result so far: 527.0
If we take 2247 away from 2513, we end up with 266.
Fetch the next digit (8) from the dividend, attach it to 266 and continue: 2668 / 321

On to step 7:
When dividing 2668 by 321, we get 8 with a remainder of 100.
Put 8 as the next digit of the answer. 
Result so far: 5278.0
If we subtract 2568 from 2668, we get 100.
Grab the next digit (1) from the dividend, add it to 100, then carry on: 1001 / 321

Let's proceed to step 8:
When dividing 1001 by 321, we get 3 with a remainder of 38.
Put 3 as the next digit of the answer. 
Result so far: 52783.0
If we subtract 963 from 1001, we get 38.
Since there are no more digits in the dividend, we add a zero to the remainder making it 380, and continue the process.

Going ahead to step 9:
321 can be fit into 380 1 times, resulting in a remainder of 59.
Put 1 as the next digit of the answer. 
Result so far: 52783.1
Subtracting 321 from 380 leaves us with 59.
Since there are no more digits in the dividend, we add a zero to the remainder making it 590, and continue the process.

On to step 10:
590 divided by 321 is 1 with a remainder of 269.
The next digit of our result is 1. 
Result so far: 52783.11
If we take 321 away from 590, we end up with 269.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2690, and continue the process.

After the division, we end up with 52783.11 and a remainder of 0.269.