143221 divided by 31 
The aim is to understand the frequency of 31 in 143221.

Moving on to step 1:
31 can be fit into 1 0 times, resulting in a remainder of 1.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtracting 0 from 1 leaves us with 1.
Bring next digit (4) of the dividend behind the 1 and repeat the process: 14 / 31

Moving on to step 2:
The number 31 fits into 14 0 times, leaving a remainder of 14.
The next digit of our result is 0. 
Result so far: 0.0
Subtract 0 from 14 to get 14.
Fetch the next digit (3) from the dividend, attach it to 14 and continue: 143 / 31

Step 3:
When dividing 143 by 31, we get 4 with a remainder of 19.
Use 4 as the next digit of our solution. 
Result so far: 4.0
If we take 124 away from 143, we end up with 19.
Append the next digit (2) from the dividend to 19 and continue with: 192 / 31

Going ahead to step 4:
31 can be fit into 192 6 times, resulting in a remainder of 6.
Put 6 as the next digit of the answer. 
Result so far: 46.0
The remainder is 6 after subtracting 186 from 192.
Fetch the next digit (2) from the dividend, attach it to 6 and continue: 62 / 31

Let's proceed to step 5:
31 goes into 62 2 times with a remainder of 0.
Write down 2 as next digit of the result. 
Result so far: 462.0
The remainder is 0 after subtracting 62 from 62.
Include the next digit (1) from the dividend after 0, then repeat: 1 / 31

On to step 6:
31 can be fit into 1 0 times, resulting in a remainder of 1.
The next digit of our result is 0. 
Result so far: 4620.0
Subtracting 0 from 1 leaves us with 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Step 7:
31 can be fit into 10 0 times, resulting in a remainder of 10.
Record the quotient 0 as the next digit in the result. 
Result so far: 4620.0
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.

Step 8:
If we divide 100 by 31, we get 3 and a remainder of 7.
The next digit of our result is 3. 
Result so far: 4620.03
If we take 93 away from 100, we end up 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 9:
If we divide 70 by 31, we get 2 and a remainder of 8.
Use 2 as the next digit of our solution. 
Result so far: 4620.032
Deduct 62 from 70 and we're left 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.

Going ahead to step 10:
If we divide 80 by 31, we get 2 and a remainder of 18.
Write down 2 as next digit of the result. 
Result so far: 4620.0322
If we subtract 62 from 80, we get 18.
Since there are no more digits in the dividend, we add a zero to the remainder making it 180, and continue the process.

After the division, we end up with 4620.0322 and a remainder of 0.00018.