We look at the division of 99390989 by 438 
The aim is to understand the frequency of 438 in 99390989.

Moving on to step 1:
When dividing 9 by 438, we get 0 with a remainder of 9.
The next digit of our result is 0. 
Result so far: 0.0
Subtract 0 from 9 to get 9.
Take the next digit (9) from the dividend and append it to 9, then repeat: 99 / 438

Step 2:
When dividing 99 by 438, we get 0 with a remainder of 99.
Write down 0 as next digit of the result. 
Result so far: 0.0
Subtracting 0 from 99 leaves us with 99.
Fetch the next digit (3) from the dividend, attach it to 99 and continue: 993 / 438

Moving on to step 3:
438 goes into 993 2 times with a remainder of 117.
Use 2 as the next digit of our solution. 
Result so far: 2.0
Subtracting 876 from 993 leaves us with 117.
Grab the next digit (9) from the dividend, add it to 117, then carry on: 1179 / 438

Advancing to step 4:
438 goes into 1179 2 times with a remainder of 303.
Use 2 as the next digit of our solution. 
Result so far: 22.0
The remainder is 303 after subtracting 876 from 1179.
Grab the next digit (0) from the dividend, add it to 303, then carry on: 3030 / 438

Moving on to step 5:
The number 438 fits into 3030 6 times, leaving a remainder of 402.
Record the quotient 6 as the next digit in the result. 
Result so far: 226.0
If we subtract 2628 from 3030, we get 402.
Take the next digit (9) from the dividend and append it to 402, then repeat: 4029 / 438

Advancing to step 6:
438 can be fit into 4029 9 times, resulting in a remainder of 87.
Use 9 as the next digit of our solution. 
Result so far: 2269.0
Deduct 3942 from 4029 and we're left with 87.
Take the next digit (8) from the dividend and append it to 87, then repeat: 878 / 438

Going ahead to step 7:
878 divided by 438 is 2 with a remainder of 2.
Put 2 as the next digit of the answer. 
Result so far: 22692.0
The remainder is 2 after subtracting 876 from 878.
Take the next digit (9) from the dividend and append it to 2, then repeat: 29 / 438

Let's proceed to step 8:
The number 438 fits into 29 0 times, leaving a remainder of 29.
Record the quotient 0 as the next digit in the result. 
Result so far: 226920.0
Deduct 0 from 29 and we're left with 29.
Since there are no more digits in the dividend, we add a zero to the remainder making it 290, and continue the process.

On to step 9:
438 can be fit into 290 0 times, resulting in a remainder of 290.
The number 0 becomes the next digit in our result. 
Result so far: 226920.0
If we subtract 0 from 290, we get 290.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2900, and continue the process.

Moving on to step 10:
When dividing 2900 by 438, we get 6 with a remainder of 272.
Use 6 as the next digit of our solution. 
Result so far: 226920.06
If we subtract 2628 from 2900, we get 272.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2720, and continue the process.

Going ahead to step 11:
2720 divided by 438 is 6 with a remainder of 92.
Use 6 as the next digit of our solution. 
Result so far: 226920.066
Deduct 2628 from 2720 and we're left with 92.
Since there are no more digits in the dividend, we add a zero to the remainder making it 920, and continue the process.

After the division, we end up with 226920.066 and a remainder of 0.0092.