We look at the division of 838373 by 90 
The aim is to understand the frequency of 90 in 838373.

Let's proceed to step 1:
If we divide 8 by 90, we get 0 and a remainder of 8.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtracting 0 from 8 leaves us with 8.
Take the next digit (3) from the dividend and append it to 8, then repeat: 83 / 90

Advancing to step 2:
83 divided by 90 is 0 with a remainder of 83.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
The remainder is 83 after subtracting 0 from 83.
Fetch the next digit (8) from the dividend, attach it to 83 and continue: 838 / 90

On to step 3:
The number 90 fits into 838 9 times, leaving a remainder of 28.
Record the quotient 9 as the next digit in the result. 
Result so far: 9.0
Subtracting 810 from 838 leaves us with 28.
Grab the next digit (3) from the dividend, add it to 28, then carry on: 283 / 90

Let's proceed to step 4:
283 divided by 90 is 3 with a remainder of 13.
Record the quotient 3 as the next digit in the result. 
Result so far: 93.0
The remainder is 13 after subtracting 270 from 283.
Grab the next digit (7) from the dividend, add it to 13, then carry on: 137 / 90

Let's proceed to step 5:
90 can be fit into 137 1 times, resulting in a remainder of 47.
The next digit of our result is 1. 
Result so far: 931.0
If we subtract 90 from 137, we get 47.
Include the next digit (3) from the dividend after 47, then repeat: 473 / 90

Step 6:
The number 90 fits into 473 5 times, leaving a remainder of 23.
Record the quotient 5 as the next digit in the result. 
Result so far: 9315.0
If we subtract 450 from 473, we get 23.
Since there are no more digits in the dividend, we add a zero to the remainder making it 230, and continue the process.

On to step 7:
The number 90 fits into 230 2 times, leaving a remainder of 50.
Write down 2 as next digit of the result. 
Result so far: 9315.2
If we take 180 away from 230, we end up with 50.
Since there are no more digits in the dividend, we add a zero to the remainder making it 500, and continue the process.

On to step 8:
When dividing 500 by 90, we get 5 with a remainder of 50.
Record the quotient 5 as the next digit in the result. 
Result so far: 9315.25
If we take 450 away from 500, we end up with 50.
Since there are no more digits in the dividend, we add a zero to the remainder making it 500, and continue the process.

Advancing to step 9:
If we divide 500 by 90, we get 5 and a remainder of 50.
Write down 5 as next digit of the result. 
Result so far: 9315.255
If we take 450 away from 500, we end up with 50.
Since there are no more digits in the dividend, we add a zero to the remainder making it 500, and continue the process.

The final result is 9315.255 with a remainder of 0.005.