Let's divide 3880129 by 903
The aim is to understand the frequency of 903 in 3880129.

On to step 1:
903 goes into 3 0 times with a remainder of 3.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
If we subtract 0 from 3, we get 3.
Bring next digit (8) of the dividend behind the 3 and repeat the process: 38 / 903

Going ahead to step 2:
903 can be fit into 38 0 times, resulting in a remainder of 38.
The next digit of our result is 0. 
Result so far: 0.0
Deduct 0 from 38 and we're left with 38.
Bring next digit (8) of the dividend behind the 38 and repeat the process: 388 / 903

Going ahead to step 3:
If we divide 388 by 903, we get 0 and a remainder of 388.
The next digit of our result is 0. 
Result so far: 0.0
Subtracting 0 from 388 leaves us with 388.
Grab the next digit (0) from the dividend, add it to 388, then carry on: 3880 / 903

On to step 4:
When dividing 3880 by 903, we get 4 with a remainder of 268.
Use 4 as the next digit of our solution. 
Result so far: 4.0
Subtracting 3612 from 3880 leaves us with 268.
Fetch the next digit (1) from the dividend, attach it to 268 and continue: 2681 / 903

Let's proceed to step 5:
903 can be fit into 2681 2 times, resulting in a remainder of 875.
The next digit of our result is 2. 
Result so far: 42.0
Subtract 1806 from 2681 to get 875.
Take the next digit (2) from the dividend and append it to 875, then repeat: 8752 / 903

Going ahead to step 6:
If we divide 8752 by 903, we get 9 and a remainder of 625.
The number 9 becomes the next digit in our result. 
Result so far: 429.0
Subtract 8127 from 8752 to get 625.
Include the next digit (9) from the dividend after 625, then repeat: 6259 / 903

On to step 7:
When dividing 6259 by 903, we get 6 with a remainder of 841.
The number 6 becomes the next digit in our result. 
Result so far: 4296.0
Subtracting 5418 from 6259 leaves us with 841.
Since there are no more digits in the dividend, we add a zero to the remainder making it 8410, and continue the process.

Moving on to step 8:
903 goes into 8410 9 times with a remainder of 283.
The next digit of our result is 9. 
Result so far: 4296.9
If we subtract 8127 from 8410, we get 283.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2830, and continue the process.

Moving on to step 9:
When dividing 2830 by 903, we get 3 with a remainder of 121.
The number 3 becomes the next digit in our result. 
Result so far: 4296.93
Subtracting 2709 from 2830 leaves us with 121.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1210, and continue the process.

Moving on to step 10:
903 goes into 1210 1 times with a remainder of 307.
Put 1 as the next digit of the answer. 
Result so far: 4296.931
Subtract 903 from 1210 to get 307.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3070, and continue the process.

Advancing to step 11:
The number 903 fits into 3070 3 times, leaving a remainder of 361.
The number 3 becomes the next digit in our result. 
Result so far: 4296.9313
Subtracting 2709 from 3070 leaves us with 361.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3610, and continue the process.

Step 12:
903 can be fit into 3610 3 times, resulting in a remainder of 901.
Use 3 as the next digit of our solution. 
Result so far: 4296.93133
If we take 2709 away from 3610, we end up with 901.
Since there are no more digits in the dividend, we add a zero to the remainder making it 9010, and continue the process.

The final result is 4296.93133 with a remainder of 0.000901.