We look at the division of 663872 by 57 
The aim is to understand the frequency of 57 in 663872.

Step 1:
When dividing 6 by 57, we get 0 with a remainder of 6.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
If we subtract 0 from 6, we get 6.
Fetch the next digit (6) from the dividend, attach it to 6 and continue: 66 / 57

Going ahead to step 2:
57 goes into 66 1 times with a remainder of 9.
The next digit of our result is 1. 
Result so far: 1.0
The remainder is 9 after subtracting 57 from 66.
Grab the next digit (3) from the dividend, add it to 9, then carry on: 93 / 57

Let's proceed to step 3:
57 goes into 93 1 times with a remainder of 36.
Record the quotient 1 as the next digit in the result. 
Result so far: 11.0
Subtract 57 from 93 to get 36.
Fetch the next digit (8) from the dividend, attach it to 36 and continue: 368 / 57

Moving on to step 4:
368 divided by 57 is 6 with a remainder of 26.
The next digit of our result is 6. 
Result so far: 116.0
If we take 342 away from 368, we end up with 26.
Grab the next digit (7) from the dividend, add it to 26, then carry on: 267 / 57

On to step 5:
If we divide 267 by 57, we get 4 and a remainder of 39.
Record the quotient 4 as the next digit in the result. 
Result so far: 1164.0
If we subtract 228 from 267, we get 39.
Fetch the next digit (2) from the dividend, attach it to 39 and continue: 392 / 57

Advancing to step 6:
392 divided by 57 is 6 with a remainder of 50.
Put 6 as the next digit of the answer. 
Result so far: 11646.0
If we subtract 342 from 392, 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.

On to step 7:
The number 57 fits into 500 8 times, leaving a remainder of 44.
Write down 8 as next digit of the result. 
Result so far: 11646.8
If we subtract 456 from 500, we get 44.
Since there are no more digits in the dividend, we add a zero to the remainder making it 440, and continue the process.

Going ahead to step 8:
57 can be fit into 440 7 times, resulting in a remainder of 41.
Use 7 as the next digit of our solution. 
Result so far: 11646.87
Subtract 399 from 440 to get 41.
Since there are no more digits in the dividend, we add a zero to the remainder making it 410, and continue the process.

Advancing to step 9:
When dividing 410 by 57, we get 7 with a remainder of 11.
Use 7 as the next digit of our solution. 
Result so far: 11646.877
If we take 399 away from 410, we end up with 11.
Since there are no more digits in the dividend, we add a zero to the remainder making it 110, and continue the process.

The quotient of the division is 11646.877, and the remainder is 0.0011.