We're dividing 43390310 by 999 
The aim is to understand the frequency of 999 in 43390310.

Moving on to step 1:
If we divide 4 by 999, we get 0 and a remainder of 4.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
The remainder is 4 after subtracting 0 from 4.
Take the next digit (3) from the dividend and append it to 4, then repeat: 43 / 999

Going ahead to step 2:
If we divide 43 by 999, we get 0 and a remainder of 43.
Write down 0 as next digit of the result. 
Result so far: 0.0
Deduct 0 from 43 and we're left with 43.
Include the next digit (3) from the dividend after 43, then repeat: 433 / 999

Moving on to step 3:
433 divided by 999 is 0 with a remainder of 433.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Deduct 0 from 433 and we're left with 433.
Include the next digit (9) from the dividend after 433, then repeat: 4339 / 999

Moving on to step 4:
4339 divided by 999 is 4 with a remainder of 343.
The number 4 becomes the next digit in our result. 
Result so far: 4.0
If we subtract 3996 from 4339, we get 343.
Grab the next digit (0) from the dividend, add it to 343, then carry on: 3430 / 999

Step 5:
999 can be fit into 3430 3 times, resulting in a remainder of 433.
Write down 3 as next digit of the result. 
Result so far: 43.0
The remainder is 433 after subtracting 2997 from 3430.
Bring next digit (3) of the dividend behind the 433 and repeat the process: 4333 / 999

Advancing to step 6:
If we divide 4333 by 999, we get 4 and a remainder of 337.
Use 4 as the next digit of our solution. 
Result so far: 434.0
Deduct 3996 from 4333 and we're left with 337.
Bring next digit (1) of the dividend behind the 337 and repeat the process: 3371 / 999

Let's proceed to step 7:
999 goes into 3371 3 times with a remainder of 374.
Use 3 as the next digit of our solution. 
Result so far: 4343.0
The remainder is 374 after subtracting 2997 from 3371.
Grab the next digit (0) from the dividend, add it to 374, then carry on: 3740 / 999

Advancing to step 8:
If we divide 3740 by 999, we get 3 and a remainder of 743.
The number 3 becomes the next digit in our result. 
Result so far: 43433.0
Subtract 2997 from 3740 to get 743.
Since there are no more digits in the dividend, we add a zero to the remainder making it 7430, and continue the process.

Moving on to step 9:
999 goes into 7430 7 times with a remainder of 437.
Put 7 as the next digit of the answer. 
Result so far: 43433.7
If we subtract 6993 from 7430, we get 437.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4370, and continue the process.

Going ahead to step 10:
When dividing 4370 by 999, we get 4 with a remainder of 374.
Record the quotient 4 as the next digit in the result. 
Result so far: 43433.74
Subtract 3996 from 4370 to get 374.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3740, and continue the process.

On to step 11:
If we divide 3740 by 999, we get 3 and a remainder of 743.
The number 3 becomes the next digit in our result. 
Result so far: 43433.743
Subtracting 2997 from 3740 leaves us with 743.
Since there are no more digits in the dividend, we add a zero to the remainder making it 7430, and continue the process.

On to step 12:
7430 divided by 999 is 7 with a remainder of 437.
The number 7 becomes the next digit in our result. 
Result so far: 43433.7437
Deduct 6993 from 7430 and we're left with 437.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4370, and continue the process.

Advancing to step 13:
4370 divided by 999 is 4 with a remainder of 374.
The next digit of our result is 4. 
Result so far: 43433.74374
Subtracting 3996 from 4370 leaves us with 374.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3740, and continue the process.

Advancing to step 14:
The number 999 fits into 3740 3 times, leaving a remainder of 743.
The next digit of our result is 3. 
Result so far: 43433.743743
If we subtract 2997 from 3740, we get 743.
Since there are no more digits in the dividend, we add a zero to the remainder making it 7430, and continue the process.

Moving on to step 15:
When dividing 7430 by 999, we get 7 with a remainder of 437.
Write down 7 as next digit of the result. 
Result so far: 43433.7437437
The remainder is 437 after subtracting 6993 from 7430.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4370, and continue the process.

Moving on to step 16:
4370 divided by 999 is 4 with a remainder of 374.
The next digit of our result is 4. 
Result so far: 43433.74374374
The remainder is 374 after subtracting 3996 from 4370.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3740, and continue the process.

In conclusion, the division gives 43433.74374374 with a balance of 3.74e-07.