643989 ÷ 22 
The aim is to understand the frequency of 22 in 643989.

Moving on to step 1:
22 can be fit into 6 0 times, resulting in a remainder of 6.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
The remainder is 6 after subtracting 0 from 6.
Grab the next digit (4) from the dividend, add it to 6, then carry on: 64 / 22

Step 2:
22 goes into 64 2 times with a remainder of 20.
Record the quotient 2 as the next digit in the result. 
Result so far: 2.0
Subtracting 44 from 64 leaves us with 20.
Grab the next digit (3) from the dividend, add it to 20, then carry on: 203 / 22

Moving on to step 3:
203 divided by 22 is 9 with a remainder of 5.
Put 9 as the next digit of the answer. 
Result so far: 29.0
Subtract 198 from 203 to get 5.
Fetch the next digit (9) from the dividend, attach it to 5 and continue: 59 / 22

Step 4:
22 goes into 59 2 times with a remainder of 15.
The next digit of our result is 2. 
Result so far: 292.0
The remainder is 15 after subtracting 44 from 59.
Fetch the next digit (8) from the dividend, attach it to 15 and continue: 158 / 22

Let's proceed to step 5:
22 can be fit into 158 7 times, resulting in a remainder of 4.
Write down 7 as next digit of the result. 
Result so far: 2927.0
The remainder is 4 after subtracting 154 from 158.
Take the next digit (9) from the dividend and append it to 4, then repeat: 49 / 22

Going ahead to step 6:
22 goes into 49 2 times with a remainder of 5.
Record the quotient 2 as the next digit in the result. 
Result so far: 29272.0
Deduct 44 from 49 and we're left with 5.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

On to step 7:
50 divided by 22 is 2 with a remainder of 6.
Write down 2 as next digit of the result. 
Result so far: 29272.2
If we subtract 44 from 50, we get 6.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

Going ahead to step 8:
60 divided by 22 is 2 with a remainder of 16.
The next digit of our result is 2. 
Result so far: 29272.22
Subtract 44 from 60 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.

After the division, we end up with 29272.22 and a remainder of 0.016.