2645661 ÷ 18 
The aim is to understand the frequency of 18 in 2645661.

On to step 1:
2 divided by 18 is 0 with a remainder of 2.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Subtract 0 from 2 to get 2.
Append the next digit (6) from the dividend to 2 and continue with: 26 / 18

Moving on to step 2:
18 goes into 26 1 times with a remainder of 8.
Put 1 as the next digit of the answer. 
Result so far: 1.0
The remainder is 8 after subtracting 18 from 26.
Take the next digit (4) from the dividend and append it to 8, then repeat: 84 / 18

Let's proceed to step 3:
18 goes into 84 4 times with a remainder of 12.
Write down 4 as next digit of the result. 
Result so far: 14.0
Deduct 72 from 84 and we're left with 12.
Bring next digit (5) of the dividend behind the 12 and repeat the process: 125 / 18

Step 4:
The number 18 fits into 125 6 times, leaving a remainder of 17.
The next digit of our result is 6. 
Result so far: 146.0
The remainder is 17 after subtracting 108 from 125.
Bring next digit (6) of the dividend behind the 17 and repeat the process: 176 / 18

Going ahead to step 5:
176 divided by 18 is 9 with a remainder of 14.
Use 9 as the next digit of our solution. 
Result so far: 1469.0
If we subtract 162 from 176, we get 14.
Grab the next digit (6) from the dividend, add it to 14, then carry on: 146 / 18

Let's proceed to step 6:
The number 18 fits into 146 8 times, leaving a remainder of 2.
Put 8 as the next digit of the answer. 
Result so far: 14698.0
If we subtract 144 from 146, we get 2.
Grab the next digit (1) from the dividend, add it to 2, then carry on: 21 / 18

Step 7:
21 divided by 18 is 1 with a remainder of 3.
Record the quotient 1 as the next digit in the result. 
Result so far: 146981.0
Subtract 18 from 21 to get 3.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

Advancing to step 8:
When dividing 30 by 18, we get 1 with a remainder of 12.
Use 1 as the next digit of our solution. 
Result so far: 146981.1
The remainder is 12 after subtracting 18 from 30.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

Step 9:
18 can be fit into 120 6 times, resulting in a remainder of 12.
The number 6 becomes the next digit in our result. 
Result so far: 146981.16
If we subtract 108 from 120, we get 12.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

On to step 10:
18 can be fit into 120 6 times, resulting in a remainder of 12.
Write down 6 as next digit of the result. 
Result so far: 146981.166
If we take 108 away from 120, we end up with 12.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

The final outcome is 146981.166, with a leftover of 0.0012.