81378026 ÷ 409 
The aim is to understand the frequency of 409 in 81378026.

Advancing to step 1:
409 can be fit into 8 0 times, resulting in a remainder of 8.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Subtracting 0 from 8 leaves us with 8.
Append the next digit (1) from the dividend to 8 and continue with: 81 / 409

Let's proceed to step 2:
409 can be fit into 81 0 times, resulting in a remainder of 81.
The next digit of our result is 0. 
Result so far: 0.0
If we subtract 0 from 81, we get 81.
Fetch the next digit (3) from the dividend, attach it to 81 and continue: 813 / 409

Step 3:
If we divide 813 by 409, we get 1 and a remainder of 404.
Write down 1 as next digit of the result. 
Result so far: 1.0
If we subtract 409 from 813, we get 404.
Fetch the next digit (7) from the dividend, attach it to 404 and continue: 4047 / 409

Step 4:
409 can be fit into 4047 9 times, resulting in a remainder of 366.
The number 9 becomes the next digit in our result. 
Result so far: 19.0
If we take 3681 away from 4047, we end up with 366.
Take the next digit (8) from the dividend and append it to 366, then repeat: 3668 / 409

Moving on to step 5:
If we divide 3668 by 409, we get 8 and a remainder of 396.
Put 8 as the next digit of the answer. 
Result so far: 198.0
The remainder is 396 after subtracting 3272 from 3668.
Append the next digit (0) from the dividend to 396 and continue with: 3960 / 409

On to step 6:
409 goes into 3960 9 times with a remainder of 279.
Use 9 as the next digit of our solution. 
Result so far: 1989.0
Subtracting 3681 from 3960 leaves us with 279.
Grab the next digit (2) from the dividend, add it to 279, then carry on: 2792 / 409

Going ahead to step 7:
The number 409 fits into 2792 6 times, leaving a remainder of 338.
Write down 6 as next digit of the result. 
Result so far: 19896.0
The remainder is 338 after subtracting 2454 from 2792.
Fetch the next digit (6) from the dividend, attach it to 338 and continue: 3386 / 409

Advancing to step 8:
409 goes into 3386 8 times with a remainder of 114.
The number 8 becomes the next digit in our result. 
Result so far: 198968.0
Subtracting 3272 from 3386 leaves us with 114.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1140, and continue the process.

Moving on to step 9:
When dividing 1140 by 409, we get 2 with a remainder of 322.
Record the quotient 2 as the next digit in the result. 
Result so far: 198968.2
Subtract 818 from 1140 to get 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 10:
3220 divided by 409 is 7 with a remainder of 357.
The number 7 becomes the next digit in our result. 
Result so far: 198968.27
Subtracting 2863 from 3220 leaves us with 357.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3570, and continue the process.

Going ahead to step 11:
409 goes into 3570 8 times with a remainder of 298.
Use 8 as the next digit of our solution. 
Result so far: 198968.278
If we subtract 3272 from 3570, we get 298.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2980, and continue the process.

On to step 12:
When dividing 2980 by 409, we get 7 with a remainder of 117.
The number 7 becomes the next digit in our result. 
Result so far: 198968.2787
Subtracting 2863 from 2980 leaves us with 117.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1170, and continue the process.

Let's proceed to step 13:
When dividing 1170 by 409, we get 2 with a remainder of 352.
Write down 2 as next digit of the result. 
Result so far: 198968.27872
If we take 818 away from 1170, we end up with 352.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3520, and continue the process.

On to step 14:
The number 409 fits into 3520 8 times, leaving a remainder of 248.
Put 8 as the next digit of the answer. 
Result so far: 198968.278728
Subtracting 3272 from 3520 leaves us with 248.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2480, and continue the process.

Going ahead to step 15:
409 can be fit into 2480 6 times, resulting in a remainder of 26.
Record the quotient 6 as the next digit in the result. 
Result so far: 198968.2787286
Subtracting 2454 from 2480 leaves us with 26.
Since there are no more digits in the dividend, we add a zero to the remainder making it 260, and continue the process.

Step 16:
260 divided by 409 is 0 with a remainder of 260.
Write down 0 as next digit of the result. 
Result so far: 198968.2787286
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.

The final outcome is 198968.2787286, with a leftover of 2.6e-07.