Let's divide 43904391 by 312
The aim is to understand the frequency of 312 in 43904391.

On to step 1:
312 goes into 4 0 times with a remainder of 4.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Subtract 0 from 4 to get 4.
Fetch the next digit (3) from the dividend, attach it to 4 and continue: 43 / 312

Moving on to step 2:
If we divide 43 by 312, we get 0 and a remainder of 43.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we take 0 away from 43, we end up with 43.
Take the next digit (9) from the dividend and append it to 43, then repeat: 439 / 312

Let's proceed to step 3:
439 divided by 312 is 1 with a remainder of 127.
The next digit of our result is 1. 
Result so far: 1.0
The remainder is 127 after subtracting 312 from 439.
Fetch the next digit (0) from the dividend, attach it to 127 and continue: 1270 / 312

Moving on to step 4:
1270 divided by 312 is 4 with a remainder of 22.
Use 4 as the next digit of our solution. 
Result so far: 14.0
Deduct 1248 from 1270 and we're left with 22.
Bring next digit (4) of the dividend behind the 22 and repeat the process: 224 / 312

On to step 5:
If we divide 224 by 312, we get 0 and a remainder of 224.
The next digit of our result is 0. 
Result so far: 140.0
The remainder is 224 after subtracting 0 from 224.
Grab the next digit (3) from the dividend, add it to 224, then carry on: 2243 / 312

Moving on to step 6:
2243 divided by 312 is 7 with a remainder of 59.
Put 7 as the next digit of the answer. 
Result so far: 1407.0
Subtract 2184 from 2243 to get 59.
Fetch the next digit (9) from the dividend, attach it to 59 and continue: 599 / 312

Going ahead to step 7:
When dividing 599 by 312, we get 1 with a remainder of 287.
The next digit of our result is 1. 
Result so far: 14071.0
The remainder is 287 after subtracting 312 from 599.
Grab the next digit (1) from the dividend, add it to 287, then carry on: 2871 / 312

Going ahead to step 8:
2871 divided by 312 is 9 with a remainder of 63.
The next digit of our result is 9. 
Result so far: 140719.0
The remainder is 63 after subtracting 2808 from 2871.
Since there are no more digits in the dividend, we add a zero to the remainder making it 630, and continue the process.

Advancing to step 9:
If we divide 630 by 312, we get 2 and a remainder of 6.
Use 2 as the next digit of our solution. 
Result so far: 140719.2
The remainder is 6 after subtracting 624 from 630.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

Advancing to step 10:
312 can be fit into 60 0 times, resulting in a remainder of 60.
Record the quotient 0 as the next digit in the result. 
Result so far: 140719.2
Subtract 0 from 60 to get 60.
Since there are no more digits in the dividend, we add a zero to the remainder making it 600, and continue the process.

On to step 11:
If we divide 600 by 312, we get 1 and a remainder of 288.
Use 1 as the next digit of our solution. 
Result so far: 140719.201
If we take 312 away from 600, we end up with 288.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2880, and continue the process.

Let's proceed to step 12:
312 goes into 2880 9 times with a remainder of 72.
Write down 9 as next digit of the result. 
Result so far: 140719.2019
Deduct 2808 from 2880 and we're left with 72.
Since there are no more digits in the dividend, we add a zero to the remainder making it 720, and continue the process.

Step 13:
The number 312 fits into 720 2 times, leaving a remainder of 96.
Write down 2 as next digit of the result. 
Result so far: 140719.20192
Subtract 624 from 720 to get 96.
Since there are no more digits in the dividend, we add a zero to the remainder making it 960, and continue the process.

Step 14:
960 divided by 312 is 3 with a remainder of 24.
Record the quotient 3 as the next digit in the result. 
Result so far: 140719.201923
Subtract 936 from 960 to get 24.
Since there are no more digits in the dividend, we add a zero to the remainder making it 240, and continue the process.

Step 15:
The number 312 fits into 240 0 times, leaving a remainder of 240.
Use 0 as the next digit of our solution. 
Result so far: 140719.201923
If we subtract 0 from 240, we get 240.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2400, and continue the process.

Moving on to step 16:
312 goes into 2400 7 times with a remainder of 216.
Record the quotient 7 as the next digit in the result. 
Result so far: 140719.20192307
The remainder is 216 after subtracting 2184 from 2400.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2160, and continue the process.

Our division results in 140719.20192307 with a remaining 2.16e-07.