We look at the division of 689909 by 31 
The aim is to understand the frequency of 31 in 689909.

On to step 1:
6 divided by 31 is 0 with a remainder of 6.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtract 0 from 6 to get 6.
Include the next digit (8) from the dividend after 6, then repeat: 68 / 31

Moving on to step 2:
If we divide 68 by 31, we get 2 and a remainder of 6.
The number 2 becomes the next digit in our result. 
Result so far: 2.0
Subtracting 62 from 68 leaves us with 6.
Append the next digit (9) from the dividend to 6 and continue with: 69 / 31

Going ahead to step 3:
If we divide 69 by 31, we get 2 and a remainder of 7.
The number 2 becomes the next digit in our result. 
Result so far: 22.0
Subtract 62 from 69 to get 7.
Take the next digit (9) from the dividend and append it to 7, then repeat: 79 / 31

Moving on to step 4:
The number 31 fits into 79 2 times, leaving a remainder of 17.
Write down 2 as next digit of the result. 
Result so far: 222.0
If we subtract 62 from 79, we get 17.
Take the next digit (0) from the dividend and append it to 17, then repeat: 170 / 31

Moving on to step 5:
When dividing 170 by 31, we get 5 with a remainder of 15.
The next digit of our result is 5. 
Result so far: 2225.0
Deduct 155 from 170 and we're left with 15.
Append the next digit (9) from the dividend to 15 and continue with: 159 / 31

On to step 6:
31 goes into 159 5 times with a remainder of 4.
The next digit of our result is 5. 
Result so far: 22255.0
If we take 155 away from 159, we end up with 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Let's proceed to step 7:
When dividing 40 by 31, we get 1 with a remainder of 9.
Write down 1 as next digit of the result. 
Result so far: 22255.1
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 8:
31 goes into 90 2 times with a remainder of 28.
The next digit of our result is 2. 
Result so far: 22255.12
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 9:
31 can be fit into 280 9 times, resulting in a remainder of 1.
Put 9 as the next digit of the answer. 
Result so far: 22255.129
Deduct 279 from 280 and we're left 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.

Advancing to step 10:
10 divided by 31 is 0 with a remainder of 10.
Use 0 as the next digit of our solution. 
Result so far: 22255.129
If we subtract 0 from 10, we 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 11:
31 can be fit into 100 3 times, resulting in a remainder of 7.
Record the quotient 3 as the next digit in the result. 
Result so far: 22255.12903
The remainder is 7 after subtracting 93 from 100.
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 12:
When dividing 70 by 31, we get 2 with a remainder of 8.
The number 2 becomes the next digit in our result. 
Result so far: 22255.129032
If we take 62 away from 70, we end up 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 13:
31 can be fit into 80 2 times, resulting in a remainder of 18.
The next digit of our result is 2. 
Result so far: 22255.1290322
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.

Our division results in 22255.1290322 with a remaining 1.8e-07.