812921 ÷ 31 
The aim is to understand the frequency of 31 in 812921.

Let's proceed to step 1:
If we divide 8 by 31, we get 0 and a remainder of 8.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we subtract 0 from 8, we get 8.
Grab the next digit (1) from the dividend, add it to 8, then carry on: 81 / 31

Going ahead to step 2:
81 divided by 31 is 2 with a remainder of 19.
Write down 2 as next digit of the result. 
Result so far: 2.0
Subtracting 62 from 81 leaves us with 19.
Bring next digit (2) of the dividend behind the 19 and repeat the process: 192 / 31

On to step 3:
192 divided by 31 is 6 with a remainder of 6.
Put 6 as the next digit of the answer. 
Result so far: 26.0
Subtract 186 from 192 to get 6.
Take the next digit (9) from the dividend and append it to 6, then repeat: 69 / 31

Moving on to step 4:
When dividing 69 by 31, we get 2 with a remainder of 7.
The number 2 becomes the next digit in our result. 
Result so far: 262.0
Subtract 62 from 69 to get 7.
Bring next digit (2) of the dividend behind the 7 and repeat the process: 72 / 31

Moving on to step 5:
If we divide 72 by 31, we get 2 and a remainder of 10.
Record the quotient 2 as the next digit in the result. 
Result so far: 2622.0
Subtracting 62 from 72 leaves us with 10.
Bring next digit (1) of the dividend behind the 10 and repeat the process: 101 / 31

Advancing to step 6:
When dividing 101 by 31, we get 3 with a remainder of 8.
The next digit of our result is 3. 
Result so far: 26223.0
If we subtract 93 from 101, we get 8.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

Let's proceed to step 7:
The number 31 fits into 80 2 times, leaving a remainder of 18.
The next digit of our result is 2. 
Result so far: 26223.2
Subtract 62 from 80 to 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.

Moving on to step 8:
180 divided by 31 is 5 with a remainder of 25.
Use 5 as the next digit of our solution. 
Result so far: 26223.25
If we take 155 away from 180, we end up with 25.
Since there are no more digits in the dividend, we add a zero to the remainder making it 250, and continue the process.

Advancing to step 9:
250 divided by 31 is 8 with a remainder of 2.
The number 8 becomes the next digit in our result. 
Result so far: 26223.258
If we subtract 248 from 250, we get 2.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

Going ahead to step 10:
If we divide 20 by 31, we get 0 and a remainder of 20.
The number 0 becomes the next digit in our result. 
Result so far: 26223.258
If we subtract 0 from 20, we get 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

Advancing to step 11:
200 divided by 31 is 6 with a remainder of 14.
Put 6 as the next digit of the answer. 
Result so far: 26223.25806
If we subtract 186 from 200, we get 14.
Since there are no more digits in the dividend, we add a zero to the remainder making it 140, and continue the process.

Advancing to step 12:
31 goes into 140 4 times with a remainder of 16.
Write down 4 as next digit of the result. 
Result so far: 26223.258064
If we take 124 away from 140, we end up with 16.
Since there are no more digits in the dividend, we add a zero to the remainder making it 160, and continue the process.

On to step 13:
31 goes into 160 5 times with a remainder of 5.
Write down 5 as next digit of the result. 
Result so far: 26223.2580645
Subtracting 155 from 160 leaves us with 5.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

Going ahead to step 14:
If we divide 50 by 31, we get 1 and a remainder of 19.
The number 1 becomes the next digit in our result. 
Result so far: 26223.25806451
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.

The final result is 26223.25806451 with a remainder of 1.9e-08.