We're dividing 399986 by 4 
The aim is to understand the frequency of 4 in 399986.

Step 1:
The number 4 fits into 3 0 times, leaving a remainder of 3.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtracting 0 from 3 leaves us with 3.
Include the next digit (9) from the dividend after 3, then repeat: 39 / 4

On to step 2:
4 can be fit into 39 9 times, resulting in a remainder of 3.
Put 9 as the next digit of the answer. 
Result so far: 9.0
Deduct 36 from 39 and we're left with 3.
Include the next digit (9) from the dividend after 3, then repeat: 39 / 4

Step 3:
39 divided by 4 is 9 with a remainder of 3.
Record the quotient 9 as the next digit in the result. 
Result so far: 99.0
If we take 36 away from 39, we end up with 3.
Append the next digit (9) from the dividend to 3 and continue with: 39 / 4

Step 4:
4 goes into 39 9 times with a remainder of 3.
The next digit of our result is 9. 
Result so far: 999.0
The remainder is 3 after subtracting 36 from 39.
Take the next digit (8) from the dividend and append it to 3, then repeat: 38 / 4

Going ahead to step 5:
When dividing 38 by 4, we get 9 with a remainder of 2.
Record the quotient 9 as the next digit in the result. 
Result so far: 9999.0
Deduct 36 from 38 and we're left with 2.
Bring next digit (6) of the dividend behind the 2 and repeat the process: 26 / 4

Advancing to step 6:
The number 4 fits into 26 6 times, leaving a remainder of 2.
Put 6 as the next digit of the answer. 
Result so far: 99996.0
Deduct 24 from 26 and we're left with 2.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

Advancing to step 7:
If we divide 20 by 4, we get 5 and a remainder of 0.
The next digit of our result is 5. 
Result so far: 99996.5
Subtract 20 from 20 to get 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Let's proceed to step 8:
4 can be fit into 0 0 times, resulting in a remainder of 0.
The number 0 becomes the next digit in our result. 
Result so far: 99996.5
If we subtract 0 from 0, we get 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Advancing to step 9:
4 can be fit into 0 0 times, resulting in a remainder of 0.
Record the quotient 0 as the next digit in the result. 
Result so far: 99996.5
The remainder is 0 after subtracting 0 from 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Our division results in 99996.5 with a remaining 0.0.