We divide 631690 by 18
The aim is to understand the frequency of 18 in 631690.

Let's proceed to step 1:
The number 18 fits into 6 0 times, leaving a remainder of 6.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Deduct 0 from 6 and we're left with 6.
Append the next digit (3) from the dividend to 6 and continue with: 63 / 18

Going ahead to step 2:
If we divide 63 by 18, we get 3 and a remainder of 9.
Use 3 as the next digit of our solution. 
Result so far: 3.0
Deduct 54 from 63 and we're left with 9.
Include the next digit (1) from the dividend after 9, then repeat: 91 / 18

Advancing to step 3:
18 goes into 91 5 times with a remainder of 1.
Use 5 as the next digit of our solution. 
Result so far: 35.0
The remainder is 1 after subtracting 90 from 91.
Bring next digit (6) of the dividend behind the 1 and repeat the process: 16 / 18

On to step 4:
When dividing 16 by 18, we get 0 with a remainder of 16.
Record the quotient 0 as the next digit in the result. 
Result so far: 350.0
If we subtract 0 from 16, we get 16.
Append the next digit (9) from the dividend to 16 and continue with: 169 / 18

On to step 5:
If we divide 169 by 18, we get 9 and a remainder of 7.
The number 9 becomes the next digit in our result. 
Result so far: 3509.0
If we take 162 away from 169, we end up with 7.
Include the next digit (0) from the dividend after 7, then repeat: 70 / 18

On to step 6:
If we divide 70 by 18, we get 3 and a remainder of 16.
Use 3 as the next digit of our solution. 
Result so far: 35093.0
If we subtract 54 from 70, we get 16.
Since there are no more digits in the dividend, we add a zero to the remainder making it 160, and continue the process.

Let's proceed to step 7:
When dividing 160 by 18, we get 8 with a remainder of 16.
The next digit of our result is 8. 
Result so far: 35093.8
Subtracting 144 from 160 leaves us 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.

Advancing to step 8:
The number 18 fits into 160 8 times, leaving a remainder of 16.
Put 8 as the next digit of the answer. 
Result so far: 35093.88
If we subtract 144 from 160, we get 16.
Since there are no more digits in the dividend, we add a zero to the remainder making it 160, and continue the process.

Our division results in 35093.88 with a remaining 0.016.