901249 ÷ 18 
The aim is to understand the frequency of 18 in 901249.

Advancing to step 1:
The number 18 fits into 9 0 times, leaving a remainder of 9.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtract 0 from 9 to get 9.
Append the next digit (0) from the dividend to 9 and continue with: 90 / 18

Let's proceed to step 2:
18 can be fit into 90 5 times, resulting in a remainder of 0.
Record the quotient 5 as the next digit in the result. 
Result so far: 5.0
The remainder is 0 after subtracting 90 from 90.
Grab the next digit (1) from the dividend, add it to 0, then carry on: 1 / 18

Moving on to step 3:
When dividing 1 by 18, we get 0 with a remainder of 1.
Record the quotient 0 as the next digit in the result. 
Result so far: 50.0
Subtracting 0 from 1 leaves us with 1.
Bring next digit (2) of the dividend behind the 1 and repeat the process: 12 / 18

Let's proceed to step 4:
18 can be fit into 12 0 times, resulting in a remainder of 12.
The next digit of our result is 0. 
Result so far: 500.0
The remainder is 12 after subtracting 0 from 12.
Grab the next digit (4) from the dividend, add it to 12, then carry on: 124 / 18

Going ahead to step 5:
18 goes into 124 6 times with a remainder of 16.
Write down 6 as next digit of the result. 
Result so far: 5006.0
If we subtract 108 from 124, we get 16.
Grab the next digit (9) from the dividend, add it to 16, then carry on: 169 / 18

Going ahead to step 6:
18 can be fit into 169 9 times, resulting in a remainder of 7.
Record the quotient 9 as the next digit in the result. 
Result so far: 50069.0
Subtracting 162 from 169 leaves us 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.

Advancing to step 7:
If we divide 70 by 18, we get 3 and a remainder of 16.
Put 3 as the next digit of the answer. 
Result so far: 50069.3
Deduct 54 from 70 and we're left 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 8:
160 divided by 18 is 8 with a remainder of 16.
Use 8 as the next digit of our solution. 
Result so far: 50069.38
Deduct 144 from 160 and we're left 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 9:
When dividing 160 by 18, we get 8 with a remainder of 16.
The number 8 becomes the next digit in our result. 
Result so far: 50069.388
Subtract 144 from 160 to 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 50069.388 with a remaining 0.0016.