We're dividing 409890 by 19 
The aim is to understand the frequency of 19 in 409890.

Step 1:
The number 19 fits into 4 0 times, leaving a remainder of 4.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtracting 0 from 4 leaves us with 4.
Fetch the next digit (0) from the dividend, attach it to 4 and continue: 40 / 19

Let's proceed to step 2:
40 divided by 19 is 2 with a remainder of 2.
Put 2 as the next digit of the answer. 
Result so far: 2.0
If we take 38 away from 40, we end up with 2.
Fetch the next digit (9) from the dividend, attach it to 2 and continue: 29 / 19

Going ahead to step 3:
29 divided by 19 is 1 with a remainder of 10.
Write down 1 as next digit of the result. 
Result so far: 21.0
If we subtract 19 from 29, we get 10.
Include the next digit (8) from the dividend after 10, then repeat: 108 / 19

Step 4:
If we divide 108 by 19, we get 5 and a remainder of 13.
Put 5 as the next digit of the answer. 
Result so far: 215.0
Subtract 95 from 108 to get 13.
Include the next digit (9) from the dividend after 13, then repeat: 139 / 19

Step 5:
When dividing 139 by 19, we get 7 with a remainder of 6.
The number 7 becomes the next digit in our result. 
Result so far: 2157.0
Subtracting 133 from 139 leaves us with 6.
Fetch the next digit (0) from the dividend, attach it to 6 and continue: 60 / 19

On to step 6:
19 can be fit into 60 3 times, resulting in a remainder of 3.
Write down 3 as next digit of the result. 
Result so far: 21573.0
The remainder is 3 after subtracting 57 from 60.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

Step 7:
The number 19 fits into 30 1 times, leaving a remainder of 11.
The number 1 becomes the next digit in our result. 
Result so far: 21573.1
If we subtract 19 from 30, we get 11.
Since there are no more digits in the dividend, we add a zero to the remainder making it 110, and continue the process.

Moving on to step 8:
19 goes into 110 5 times with a remainder of 15.
Record the quotient 5 as the next digit in the result. 
Result so far: 21573.15
If we take 95 away from 110, we end up with 15.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

Going ahead to step 9:
If we divide 150 by 19, we get 7 and a remainder of 17.
Record the quotient 7 as the next digit in the result. 
Result so far: 21573.157
The remainder is 17 after subtracting 133 from 150.
Since there are no more digits in the dividend, we add a zero to the remainder making it 170, and continue the process.

Moving on to step 10:
19 can be fit into 170 8 times, resulting in a remainder of 18.
Record the quotient 8 as the next digit in the result. 
Result so far: 21573.1578
If we take 152 away from 170, we end up 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.

On to step 11:
180 divided by 19 is 9 with a remainder of 9.
The number 9 becomes the next digit in our result. 
Result so far: 21573.15789
Subtracting 171 from 180 leaves us with 9.
Since there are no more digits in the dividend, we add a zero to the remainder making it 90, and continue the process.

Going ahead to step 12:
19 goes into 90 4 times with a remainder of 14.
The number 4 becomes the next digit in our result. 
Result so far: 21573.157894
Subtracting 76 from 90 leaves us with 14.
Since there are no more digits in the dividend, we add a zero to the remainder making it 140, and continue the process.

On to step 13:
19 can be fit into 140 7 times, resulting in a remainder of 7.
Write down 7 as next digit of the result. 
Result so far: 21573.1578947
Subtracting 133 from 140 leaves us with 7.
Since there are no more digits in the dividend, we add a zero to the remainder making it 70, and continue the process.

Going ahead to step 14:
70 divided by 19 is 3 with a remainder of 13.
The next digit of our result is 3. 
Result so far: 21573.15789473
Subtracting 57 from 70 leaves us with 13.
Since there are no more digits in the dividend, we add a zero to the remainder making it 130, and continue the process.

The final result is 21573.15789473 with a remainder of 1.3e-08.