We're dividing 64236251 by 409 
The aim is to understand the frequency of 409 in 64236251.

Let's proceed to step 1:
When dividing 6 by 409, we get 0 with a remainder of 6.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
The remainder is 6 after subtracting 0 from 6.
Bring next digit (4) of the dividend behind the 6 and repeat the process: 64 / 409

On to step 2:
409 can be fit into 64 0 times, resulting in a remainder of 64.
The next digit of our result is 0. 
Result so far: 0.0
If we subtract 0 from 64, we get 64.
Take the next digit (2) from the dividend and append it to 64, then repeat: 642 / 409

On to step 3:
409 can be fit into 642 1 times, resulting in a remainder of 233.
Record the quotient 1 as the next digit in the result. 
Result so far: 1.0
Subtract 409 from 642 to get 233.
Append the next digit (3) from the dividend to 233 and continue with: 2333 / 409

Advancing to step 4:
When dividing 2333 by 409, we get 5 with a remainder of 288.
Put 5 as the next digit of the answer. 
Result so far: 15.0
Deduct 2045 from 2333 and we're left with 288.
Include the next digit (6) from the dividend after 288, then repeat: 2886 / 409

Going ahead to step 5:
409 goes into 2886 7 times with a remainder of 23.
The number 7 becomes the next digit in our result. 
Result so far: 157.0
If we take 2863 away from 2886, we end up with 23.
Bring next digit (2) of the dividend behind the 23 and repeat the process: 232 / 409

Going ahead to step 6:
409 can be fit into 232 0 times, resulting in a remainder of 232.
Record the quotient 0 as the next digit in the result. 
Result so far: 1570.0
If we take 0 away from 232, we end up with 232.
Grab the next digit (5) from the dividend, add it to 232, then carry on: 2325 / 409

Let's proceed to step 7:
When dividing 2325 by 409, we get 5 with a remainder of 280.
Put 5 as the next digit of the answer. 
Result so far: 15705.0
If we take 2045 away from 2325, we end up with 280.
Grab the next digit (1) from the dividend, add it to 280, then carry on: 2801 / 409

Advancing to step 8:
When dividing 2801 by 409, we get 6 with a remainder of 347.
Record the quotient 6 as the next digit in the result. 
Result so far: 157056.0
The remainder is 347 after subtracting 2454 from 2801.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3470, and continue the process.

Step 9:
If we divide 3470 by 409, we get 8 and a remainder of 198.
The next digit of our result is 8. 
Result so far: 157056.8
If we subtract 3272 from 3470, we get 198.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1980, and continue the process.

On to step 10:
The number 409 fits into 1980 4 times, leaving a remainder of 344.
Use 4 as the next digit of our solution. 
Result so far: 157056.84
If we take 1636 away from 1980, we end up with 344.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3440, and continue the process.

On to step 11:
When dividing 3440 by 409, we get 8 with a remainder of 168.
Record the quotient 8 as the next digit in the result. 
Result so far: 157056.848
The remainder is 168 after subtracting 3272 from 3440.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1680, and continue the process.

Advancing to step 12:
If we divide 1680 by 409, we get 4 and a remainder of 44.
Write down 4 as next digit of the result. 
Result so far: 157056.8484
Deduct 1636 from 1680 and we're left with 44.
Since there are no more digits in the dividend, we add a zero to the remainder making it 440, and continue the process.

On to step 13:
440 divided by 409 is 1 with a remainder of 31.
Write down 1 as next digit of the result. 
Result so far: 157056.84841
Deduct 409 from 440 and we're left with 31.
Since there are no more digits in the dividend, we add a zero to the remainder making it 310, and continue the process.

Let's proceed to step 14:
409 can be fit into 310 0 times, resulting in a remainder of 310.
Record the quotient 0 as the next digit in the result. 
Result so far: 157056.84841
Subtract 0 from 310 to get 310.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3100, and continue the process.

Step 15:
409 goes into 3100 7 times with a remainder of 237.
Record the quotient 7 as the next digit in the result. 
Result so far: 157056.8484107
Subtract 2863 from 3100 to get 237.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2370, and continue the process.

Advancing to step 16:
If we divide 2370 by 409, we get 5 and a remainder of 325.
Put 5 as the next digit of the answer. 
Result so far: 157056.84841075
Subtracting 2045 from 2370 leaves us with 325.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3250, and continue the process.

The final result is 157056.84841075 with a remainder of 3.25e-07.