438398 divided by 31 
The aim is to understand the frequency of 31 in 438398.

On to step 1:
When dividing 4 by 31, we get 0 with a remainder of 4.
The number 0 becomes the next digit in our 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 / 31

On to step 2:
31 can be fit into 43 1 times, resulting in a remainder of 12.
The number 1 becomes the next digit in our result. 
Result so far: 1.0
Subtract 31 from 43 to get 12.
Take the next digit (8) from the dividend and append it to 12, then repeat: 128 / 31

Moving on to step 3:
128 divided by 31 is 4 with a remainder of 4.
Put 4 as the next digit of the answer. 
Result so far: 14.0
If we take 124 away from 128, we end up with 4.
Append the next digit (3) from the dividend to 4 and continue with: 43 / 31

Advancing to step 4:
31 can be fit into 43 1 times, resulting in a remainder of 12.
Use 1 as the next digit of our solution. 
Result so far: 141.0
Subtract 31 from 43 to get 12.
Bring next digit (9) of the dividend behind the 12 and repeat the process: 129 / 31

Moving on to step 5:
If we divide 129 by 31, we get 4 and a remainder of 5.
Use 4 as the next digit of our solution. 
Result so far: 1414.0
If we subtract 124 from 129, we get 5.
Grab the next digit (8) from the dividend, add it to 5, then carry on: 58 / 31

Advancing to step 6:
31 can be fit into 58 1 times, resulting in a remainder of 27.
Record the quotient 1 as the next digit in the result. 
Result so far: 14141.0
If we subtract 31 from 58, we get 27.
Since there are no more digits in the dividend, we add a zero to the remainder making it 270, and continue the process.

Moving on to step 7:
When dividing 270 by 31, we get 8 with a remainder of 22.
Put 8 as the next digit of the answer. 
Result so far: 14141.8
The remainder is 22 after subtracting 248 from 270.
Since there are no more digits in the dividend, we add a zero to the remainder making it 220, and continue the process.

Going ahead to step 8:
The number 31 fits into 220 7 times, leaving a remainder of 3.
The next digit of our result is 7. 
Result so far: 14141.87
Deduct 217 from 220 and we're left with 3.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

Let's proceed to step 9:
31 can be fit into 30 0 times, resulting in a remainder of 30.
Use 0 as the next digit of our solution. 
Result so far: 14141.87
If we subtract 0 from 30, we get 30.
Since there are no more digits in the dividend, we add a zero to the remainder making it 300, and continue the process.

Going ahead to step 10:
300 divided by 31 is 9 with a remainder of 21.
Put 9 as the next digit of the answer. 
Result so far: 14141.8709
If we take 279 away from 300, we end up with 21.
Since there are no more digits in the dividend, we add a zero to the remainder making it 210, and continue the process.

Going ahead to step 11:
31 goes into 210 6 times with a remainder of 24.
Put 6 as the next digit of the answer. 
Result so far: 14141.87096
Subtract 186 from 210 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.

Going ahead to step 12:
31 goes into 240 7 times with a remainder of 23.
The number 7 becomes the next digit in our result. 
Result so far: 14141.870967
Subtracting 217 from 240 leaves us with 23.
Since there are no more digits in the dividend, we add a zero to the remainder making it 230, and continue the process.

Going ahead to step 13:
The number 31 fits into 230 7 times, leaving a remainder of 13.
The number 7 becomes the next digit in our result. 
Result so far: 14141.8709677
The remainder is 13 after subtracting 217 from 230.
Since there are no more digits in the dividend, we add a zero to the remainder making it 130, and continue the process.

The final outcome is 14141.8709677, with a leftover of 1.3e-07.