391387 divided by 75 
The aim is to understand the frequency of 75 in 391387.

Step 1:
75 can be fit into 3 0 times, resulting in a remainder of 3.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtracting 0 from 3 leaves us with 3.
Append the next digit (9) from the dividend to 3 and continue with: 39 / 75

Advancing to step 2:
39 divided by 75 is 0 with a remainder of 39.
Use 0 as the next digit of our solution. 
Result so far: 0.0
If we subtract 0 from 39, we get 39.
Fetch the next digit (1) from the dividend, attach it to 39 and continue: 391 / 75

Moving on to step 3:
If we divide 391 by 75, we get 5 and a remainder of 16.
Use 5 as the next digit of our solution. 
Result so far: 5.0
Deduct 375 from 391 and we're left with 16.
Grab the next digit (3) from the dividend, add it to 16, then carry on: 163 / 75

Moving on to step 4:
If we divide 163 by 75, we get 2 and a remainder of 13.
Put 2 as the next digit of the answer. 
Result so far: 52.0
Deduct 150 from 163 and we're left with 13.
Grab the next digit (8) from the dividend, add it to 13, then carry on: 138 / 75

On to step 5:
When dividing 138 by 75, we get 1 with a remainder of 63.
The next digit of our result is 1. 
Result so far: 521.0
If we subtract 75 from 138, we get 63.
Append the next digit (7) from the dividend to 63 and continue with: 637 / 75

Going ahead to step 6:
The number 75 fits into 637 8 times, leaving a remainder of 37.
The next digit of our result is 8. 
Result so far: 5218.0
The remainder is 37 after subtracting 600 from 637.
Since there are no more digits in the dividend, we add a zero to the remainder making it 370, and continue the process.

Moving on to step 7:
75 goes into 370 4 times with a remainder of 70.
Use 4 as the next digit of our solution. 
Result so far: 5218.4
Deduct 300 from 370 and we're left with 70.
Since there are no more digits in the dividend, we add a zero to the remainder making it 700, and continue the process.

Moving on to step 8:
The number 75 fits into 700 9 times, leaving a remainder of 25.
Put 9 as the next digit of the answer. 
Result so far: 5218.49
If we subtract 675 from 700, we get 25.
Since there are no more digits in the dividend, we add a zero to the remainder making it 250, and continue the process.

Advancing to step 9:
When dividing 250 by 75, we get 3 with a remainder of 25.
Put 3 as the next digit of the answer. 
Result so far: 5218.493
If we subtract 225 from 250, we get 25.
Since there are no more digits in the dividend, we add a zero to the remainder making it 250, and continue the process.

Advancing to step 10:
75 can be fit into 250 3 times, resulting in a remainder of 25.
Use 3 as the next digit of our solution. 
Result so far: 5218.4933
Subtracting 225 from 250 leaves us with 25.
Since there are no more digits in the dividend, we add a zero to the remainder making it 250, and continue the process.

The final result is 5218.4933 with a remainder of 0.00025.