We divide 645663 by 31
The aim is to understand the frequency of 31 in 645663.

Advancing to step 1:
31 can be fit into 6 0 times, resulting in a remainder of 6.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
If we take 0 away from 6, we end up with 6.
Bring next digit (4) of the dividend behind the 6 and repeat the process: 64 / 31

Moving on to step 2:
The number 31 fits into 64 2 times, leaving a remainder of 2.
Write down 2 as next digit of the result. 
Result so far: 2.0
Subtract 62 from 64 to get 2.
Bring next digit (5) of the dividend behind the 2 and repeat the process: 25 / 31

Advancing to step 3:
The number 31 fits into 25 0 times, leaving a remainder of 25.
Write down 0 as next digit of the result. 
Result so far: 20.0
If we subtract 0 from 25, we get 25.
Bring next digit (6) of the dividend behind the 25 and repeat the process: 256 / 31

Let's proceed to step 4:
256 divided by 31 is 8 with a remainder of 8.
Write down 8 as next digit of the result. 
Result so far: 208.0
If we take 248 away from 256, we end up with 8.
Take the next digit (6) from the dividend and append it to 8, then repeat: 86 / 31

Step 5:
The number 31 fits into 86 2 times, leaving a remainder of 24.
Write down 2 as next digit of the result. 
Result so far: 2082.0
Deduct 62 from 86 and we're left with 24.
Bring next digit (3) of the dividend behind the 24 and repeat the process: 243 / 31

On to step 6:
243 divided by 31 is 7 with a remainder of 26.
Use 7 as the next digit of our solution. 
Result so far: 20827.0
If we subtract 217 from 243, we get 26.
Since there are no more digits in the dividend, we add a zero to the remainder making it 260, and continue the process.

Step 7:
When dividing 260 by 31, we get 8 with a remainder of 12.
The number 8 becomes the next digit in our result. 
Result so far: 20827.8
The remainder is 12 after subtracting 248 from 260.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

Going ahead to step 8:
The number 31 fits into 120 3 times, leaving a remainder of 27.
Write down 3 as next digit of the result. 
Result so far: 20827.83
If we subtract 93 from 120, 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 9:
31 goes into 270 8 times with a remainder of 22.
Write down 8 as next digit of the result. 
Result so far: 20827.838
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.

Let's proceed to step 10:
31 goes into 220 7 times with a remainder of 3.
The next digit of our result is 7. 
Result so far: 20827.8387
Subtracting 217 from 220 leaves us 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.

Moving on to step 11:
When dividing 30 by 31, we get 0 with a remainder of 30.
The number 0 becomes the next digit in our result. 
Result so far: 20827.8387
The remainder is 30 after subtracting 0 from 30.
Since there are no more digits in the dividend, we add a zero to the remainder making it 300, and continue the process.

Advancing to step 12:
The number 31 fits into 300 9 times, leaving a remainder of 21.
The number 9 becomes the next digit in our result. 
Result so far: 20827.838709
Deduct 279 from 300 and we're left 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.

Advancing to step 13:
The number 31 fits into 210 6 times, leaving a remainder of 24.
Write down 6 as next digit of the result. 
Result so far: 20827.8387096
Subtracting 186 from 210 leaves us with 24.
Since there are no more digits in the dividend, we add a zero to the remainder making it 240, and continue the process.

Step 14:
31 goes into 240 7 times with a remainder of 23.
Write down 7 as next digit of the result. 
Result so far: 20827.83870967
Deduct 217 from 240 and we're left 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.

The final outcome is 20827.83870967, with a leftover of 2.3e-08.