We're dividing 64513643 by 391 
The aim is to understand the frequency of 391 in 64513643.

Step 1:
391 can be fit into 6 0 times, resulting in a remainder of 6.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtract 0 from 6 to get 6.
Grab the next digit (4) from the dividend, add it to 6, then carry on: 64 / 391

Step 2:
When dividing 64 by 391, we get 0 with a remainder of 64.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
If we subtract 0 from 64, we get 64.
Grab the next digit (5) from the dividend, add it to 64, then carry on: 645 / 391

On to step 3:
391 goes into 645 1 times with a remainder of 254.
Record the quotient 1 as the next digit in the result. 
Result so far: 1.0
If we subtract 391 from 645, we get 254.
Grab the next digit (1) from the dividend, add it to 254, then carry on: 2541 / 391

Step 4:
When dividing 2541 by 391, we get 6 with a remainder of 195.
Use 6 as the next digit of our solution. 
Result so far: 16.0
If we subtract 2346 from 2541, we get 195.
Take the next digit (3) from the dividend and append it to 195, then repeat: 1953 / 391

On to step 5:
1953 divided by 391 is 4 with a remainder of 389.
Use 4 as the next digit of our solution. 
Result so far: 164.0
Subtracting 1564 from 1953 leaves us with 389.
Take the next digit (6) from the dividend and append it to 389, then repeat: 3896 / 391

Let's proceed to step 6:
If we divide 3896 by 391, we get 9 and a remainder of 377.
The number 9 becomes the next digit in our result. 
Result so far: 1649.0
If we subtract 3519 from 3896, we get 377.
Grab the next digit (4) from the dividend, add it to 377, then carry on: 3774 / 391

On to step 7:
When dividing 3774 by 391, we get 9 with a remainder of 255.
The next digit of our result is 9. 
Result so far: 16499.0
If we take 3519 away from 3774, we end up with 255.
Grab the next digit (3) from the dividend, add it to 255, then carry on: 2553 / 391

Step 8:
If we divide 2553 by 391, we get 6 and a remainder of 207.
Put 6 as the next digit of the answer. 
Result so far: 164996.0
Deduct 2346 from 2553 and we're left with 207.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2070, and continue the process.

Advancing to step 9:
The number 391 fits into 2070 5 times, leaving a remainder of 115.
The next digit of our result is 5. 
Result so far: 164996.5
If we subtract 1955 from 2070, we get 115.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1150, and continue the process.

Advancing to step 10:
391 goes into 1150 2 times with a remainder of 368.
The number 2 becomes the next digit in our result. 
Result so far: 164996.52
Deduct 782 from 1150 and we're left with 368.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3680, and continue the process.

Advancing to step 11:
When dividing 3680 by 391, we get 9 with a remainder of 161.
The next digit of our result is 9. 
Result so far: 164996.529
Subtract 3519 from 3680 to get 161.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1610, and continue the process.

Moving on to step 12:
391 can be fit into 1610 4 times, resulting in a remainder of 46.
Write down 4 as next digit of the result. 
Result so far: 164996.5294
Subtract 1564 from 1610 to get 46.
Since there are no more digits in the dividend, we add a zero to the remainder making it 460, and continue the process.

Let's proceed to step 13:
391 can be fit into 460 1 times, resulting in a remainder of 69.
The next digit of our result is 1. 
Result so far: 164996.52941
Subtracting 391 from 460 leaves us with 69.
Since there are no more digits in the dividend, we add a zero to the remainder making it 690, and continue the process.

On to step 14:
391 can be fit into 690 1 times, resulting in a remainder of 299.
Write down 1 as next digit of the result. 
Result so far: 164996.529411
If we take 391 away from 690, we end up with 299.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2990, and continue the process.

The final result is 164996.529411 with a remainder of 2.99e-05.