98686438 divided by 90 
The aim is to understand the frequency of 90 in 98686438.

Let's proceed to step 1:
90 can be fit into 9 0 times, resulting in a remainder of 9.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Subtract 0 from 9 to get 9.
Grab the next digit (8) from the dividend, add it to 9, then carry on: 98 / 90

Going ahead to step 2:
90 can be fit into 98 1 times, resulting in a remainder of 8.
Record the quotient 1 as the next digit in the result. 
Result so far: 1.0
If we take 90 away from 98, we end up with 8.
Bring next digit (6) of the dividend behind the 8 and repeat the process: 86 / 90

Advancing to step 3:
90 can be fit into 86 0 times, resulting in a remainder of 86.
Put 0 as the next digit of the answer. 
Result so far: 10.0
If we take 0 away from 86, we end up with 86.
Bring next digit (8) of the dividend behind the 86 and repeat the process: 868 / 90

Step 4:
868 divided by 90 is 9 with a remainder of 58.
Use 9 as the next digit of our solution. 
Result so far: 109.0
If we take 810 away from 868, we end up with 58.
Grab the next digit (6) from the dividend, add it to 58, then carry on: 586 / 90

Step 5:
90 goes into 586 6 times with a remainder of 46.
The number 6 becomes the next digit in our result. 
Result so far: 1096.0
Subtracting 540 from 586 leaves us with 46.
Grab the next digit (4) from the dividend, add it to 46, then carry on: 464 / 90

Step 6:
The number 90 fits into 464 5 times, leaving a remainder of 14.
The number 5 becomes the next digit in our result. 
Result so far: 10965.0
The remainder is 14 after subtracting 450 from 464.
Take the next digit (3) from the dividend and append it to 14, then repeat: 143 / 90

Step 7:
90 goes into 143 1 times with a remainder of 53.
Use 1 as the next digit of our solution. 
Result so far: 109651.0
Subtract 90 from 143 to get 53.
Take the next digit (8) from the dividend and append it to 53, then repeat: 538 / 90

Advancing to step 8:
When dividing 538 by 90, we get 5 with a remainder of 88.
Write down 5 as next digit of the result. 
Result so far: 1096515.0
If we take 450 away from 538, we end up with 88.
Since there are no more digits in the dividend, we add a zero to the remainder making it 880, and continue the process.

Going ahead to step 9:
The number 90 fits into 880 9 times, leaving a remainder of 70.
Write down 9 as next digit of the result. 
Result so far: 1096515.9
If we take 810 away from 880, we end up with 70.
Since there are no more digits in the dividend, we add a zero to the remainder making it 700, and continue the process.

Let's proceed to step 10:
The number 90 fits into 700 7 times, leaving a remainder of 70.
Put 7 as the next digit of the answer. 
Result so far: 1096515.97
Subtracting 630 from 700 leaves us with 70.
Since there are no more digits in the dividend, we add a zero to the remainder making it 700, and continue the process.

Advancing to step 11:
90 can be fit into 700 7 times, resulting in a remainder of 70.
The next digit of our result is 7. 
Result so far: 1096515.977
The remainder is 70 after subtracting 630 from 700.
Since there are no more digits in the dividend, we add a zero to the remainder making it 700, and continue the process.

After the division, we end up with 1096515.977 and a remainder of 0.007.