We're dividing 143580 by 31 
The aim is to understand the frequency of 31 in 143580.

Step 1:
31 can be fit into 1 0 times, resulting in a remainder of 1.
Write down 0 as next digit of the result. 
Result so far: 0.0
Deduct 0 from 1 and we're left with 1.
Include the next digit (4) from the dividend after 1, then repeat: 14 / 31

Going ahead to step 2:
14 divided by 31 is 0 with a remainder of 14.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
The remainder is 14 after subtracting 0 from 14.
Take the next digit (3) from the dividend and append it to 14, then repeat: 143 / 31

Let's proceed to step 3:
When dividing 143 by 31, we get 4 with a remainder of 19.
Put 4 as the next digit of the answer. 
Result so far: 4.0
Deduct 124 from 143 and we're left with 19.
Append the next digit (5) from the dividend to 19 and continue with: 195 / 31

Moving on to step 4:
The number 31 fits into 195 6 times, leaving a remainder of 9.
Write down 6 as next digit of the result. 
Result so far: 46.0
Subtract 186 from 195 to get 9.
Include the next digit (8) from the dividend after 9, then repeat: 98 / 31

Going ahead to step 5:
98 divided by 31 is 3 with a remainder of 5.
Put 3 as the next digit of the answer. 
Result so far: 463.0
If we take 93 away from 98, we end up with 5.
Append the next digit (0) from the dividend to 5 and continue with: 50 / 31

On to step 6:
When dividing 50 by 31, we get 1 with a remainder of 19.
Record the quotient 1 as the next digit in the result. 
Result so far: 4631.0
Deduct 31 from 50 and we're left with 19.
Since there are no more digits in the dividend, we add a zero to the remainder making it 190, and continue the process.

On to step 7:
If we divide 190 by 31, we get 6 and a remainder of 4.
Use 6 as the next digit of our solution. 
Result so far: 4631.6
If we subtract 186 from 190, we get 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Step 8:
40 divided by 31 is 1 with a remainder of 9.
Record the quotient 1 as the next digit in the result. 
Result so far: 4631.61
If we subtract 31 from 40, we get 9.
Since there are no more digits in the dividend, we add a zero to the remainder making it 90, and continue the process.

Advancing to step 9:
31 goes into 90 2 times with a remainder of 28.
Record the quotient 2 as the next digit in the result. 
Result so far: 4631.612
If we subtract 62 from 90, we get 28.
Since there are no more digits in the dividend, we add a zero to the remainder making it 280, and continue the process.

Advancing to step 10:
31 goes into 280 9 times with a remainder of 1.
Use 9 as the next digit of our solution. 
Result so far: 4631.6129
If we subtract 279 from 280, we get 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Going ahead to step 11:
The number 31 fits into 10 0 times, leaving a remainder of 10.
The number 0 becomes the next digit in our result. 
Result so far: 4631.6129
Subtract 0 from 10 to get 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

On to step 12:
31 can be fit into 100 3 times, resulting in a remainder of 7.
Use 3 as the next digit of our solution. 
Result so far: 4631.612903
Subtracting 93 from 100 leaves us with 7.
Since there are no more digits in the dividend, we add a zero to the remainder making it 70, and continue the process.

On to step 13:
31 can be fit into 70 2 times, resulting in a remainder of 8.
Put 2 as the next digit of the answer. 
Result so far: 4631.6129032
Subtracting 62 from 70 leaves us with 8.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

On to step 14:
If we divide 80 by 31, we get 2 and a remainder of 18.
The number 2 becomes the next digit in our result. 
Result so far: 4631.61290322
Deduct 62 from 80 and we're left with 18.
Since there are no more digits in the dividend, we add a zero to the remainder making it 180, and continue the process.

The final result is 4631.61290322 with a remainder of 1.8e-08.