91704857 divided by 639 
The aim is to understand the frequency of 639 in 91704857.

On to step 1:
If we divide 9 by 639, we get 0 and a remainder of 9.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Deduct 0 from 9 and we're left with 9.
Take the next digit (1) from the dividend and append it to 9, then repeat: 91 / 639

Advancing to step 2:
91 divided by 639 is 0 with a remainder of 91.
The next digit of our result is 0. 
Result so far: 0.0
If we take 0 away from 91, we end up with 91.
Grab the next digit (7) from the dividend, add it to 91, then carry on: 917 / 639

On to step 3:
If we divide 917 by 639, we get 1 and a remainder of 278.
The next digit of our result is 1. 
Result so far: 1.0
Subtract 639 from 917 to get 278.
Fetch the next digit (0) from the dividend, attach it to 278 and continue: 2780 / 639

Let's proceed to step 4:
2780 divided by 639 is 4 with a remainder of 224.
The next digit of our result is 4. 
Result so far: 14.0
Subtract 2556 from 2780 to get 224.
Grab the next digit (4) from the dividend, add it to 224, then carry on: 2244 / 639

Step 5:
The number 639 fits into 2244 3 times, leaving a remainder of 327.
Put 3 as the next digit of the answer. 
Result so far: 143.0
Subtract 1917 from 2244 to get 327.
Grab the next digit (8) from the dividend, add it to 327, then carry on: 3278 / 639

On to step 6:
The number 639 fits into 3278 5 times, leaving a remainder of 83.
Use 5 as the next digit of our solution. 
Result so far: 1435.0
Subtracting 3195 from 3278 leaves us with 83.
Fetch the next digit (5) from the dividend, attach it to 83 and continue: 835 / 639

Step 7:
If we divide 835 by 639, we get 1 and a remainder of 196.
The next digit of our result is 1. 
Result so far: 14351.0
If we take 639 away from 835, we end up with 196.
Fetch the next digit (7) from the dividend, attach it to 196 and continue: 1967 / 639

Going ahead to step 8:
639 can be fit into 1967 3 times, resulting in a remainder of 50.
The number 3 becomes the next digit in our result. 
Result so far: 143513.0
If we subtract 1917 from 1967, we get 50.
Since there are no more digits in the dividend, we add a zero to the remainder making it 500, and continue the process.

Let's proceed to step 9:
When dividing 500 by 639, we get 0 with a remainder of 500.
The number 0 becomes the next digit in our result. 
Result so far: 143513.0
Deduct 0 from 500 and we're left with 500.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5000, and continue the process.

Let's proceed to step 10:
The number 639 fits into 5000 7 times, leaving a remainder of 527.
Write down 7 as next digit of the result. 
Result so far: 143513.07
If we take 4473 away from 5000, we end up with 527.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5270, and continue the process.

On to step 11:
639 can be fit into 5270 8 times, resulting in a remainder of 158.
Write down 8 as next digit of the result. 
Result so far: 143513.078
Subtracting 5112 from 5270 leaves us with 158.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1580, and continue the process.

Moving on to step 12:
When dividing 1580 by 639, we get 2 with a remainder of 302.
Record the quotient 2 as the next digit in the result. 
Result so far: 143513.0782
If we take 1278 away from 1580, we end up with 302.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3020, and continue the process.

Advancing to step 13:
When dividing 3020 by 639, we get 4 with a remainder of 464.
Record the quotient 4 as the next digit in the result. 
Result so far: 143513.07824
Deduct 2556 from 3020 and we're left with 464.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4640, and continue the process.

Moving on to step 14:
When dividing 4640 by 639, we get 7 with a remainder of 167.
The number 7 becomes the next digit in our result. 
Result so far: 143513.078247
Subtracting 4473 from 4640 leaves us with 167.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1670, and continue the process.

Step 15:
639 goes into 1670 2 times with a remainder of 392.
Record the quotient 2 as the next digit in the result. 
Result so far: 143513.0782472
The remainder is 392 after subtracting 1278 from 1670.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3920, and continue the process.

Advancing to step 16:
The number 639 fits into 3920 6 times, leaving a remainder of 86.
Write down 6 as next digit of the result. 
Result so far: 143513.07824726
The remainder is 86 after subtracting 3834 from 3920.
Since there are no more digits in the dividend, we add a zero to the remainder making it 860, and continue the process.

Our division results in 143513.07824726 with a remaining 8.6e-08.