We divide 78174565 by 638
The aim is to understand the frequency of 638 in 78174565.

Step 1:
7 divided by 638 is 0 with a remainder of 7.
The next digit of our result is 0. 
Result so far: 0.0
Deduct 0 from 7 and we're left with 7.
Include the next digit (8) from the dividend after 7, then repeat: 78 / 638

Going ahead to step 2:
If we divide 78 by 638, we get 0 and a remainder of 78.
Put 0 as the next digit of the answer. 
Result so far: 0.0
The remainder is 78 after subtracting 0 from 78.
Grab the next digit (1) from the dividend, add it to 78, then carry on: 781 / 638

On to step 3:
781 divided by 638 is 1 with a remainder of 143.
The next digit of our result is 1. 
Result so far: 1.0
If we subtract 638 from 781, we get 143.
Grab the next digit (7) from the dividend, add it to 143, then carry on: 1437 / 638

Advancing to step 4:
638 can be fit into 1437 2 times, resulting in a remainder of 161.
The number 2 becomes the next digit in our result. 
Result so far: 12.0
Subtract 1276 from 1437 to get 161.
Grab the next digit (4) from the dividend, add it to 161, then carry on: 1614 / 638

On to step 5:
The number 638 fits into 1614 2 times, leaving a remainder of 338.
Write down 2 as next digit of the result. 
Result so far: 122.0
The remainder is 338 after subtracting 1276 from 1614.
Include the next digit (5) from the dividend after 338, then repeat: 3385 / 638

Step 6:
638 goes into 3385 5 times with a remainder of 195.
Put 5 as the next digit of the answer. 
Result so far: 1225.0
If we take 3190 away from 3385, we end up with 195.
Append the next digit (6) from the dividend to 195 and continue with: 1956 / 638

Moving on to step 7:
638 goes into 1956 3 times with a remainder of 42.
The number 3 becomes the next digit in our result. 
Result so far: 12253.0
If we take 1914 away from 1956, we end up with 42.
Include the next digit (5) from the dividend after 42, then repeat: 425 / 638

Step 8:
638 can be fit into 425 0 times, resulting in a remainder of 425.
Put 0 as the next digit of the answer. 
Result so far: 122530.0
Deduct 0 from 425 and we're left with 425.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4250, and continue the process.

Going ahead to step 9:
638 can be fit into 4250 6 times, resulting in a remainder of 422.
Record the quotient 6 as the next digit in the result. 
Result so far: 122530.6
Subtracting 3828 from 4250 leaves us with 422.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4220, and continue the process.

Step 10:
When dividing 4220 by 638, we get 6 with a remainder of 392.
Put 6 as the next digit of the answer. 
Result so far: 122530.66
Subtracting 3828 from 4220 leaves us with 392.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3920, and continue the process.

The final result is 122530.66 with a remainder of 0.392.