Let's divide 405089 by 90
The aim is to understand the frequency of 90 in 405089.

Advancing to step 1:
4 divided by 90 is 0 with a remainder of 4.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Subtract 0 from 4 to get 4.
Append the next digit (0) from the dividend to 4 and continue with: 40 / 90

Step 2:
40 divided by 90 is 0 with a remainder of 40.
Write down 0 as next digit of the result. 
Result so far: 0.0
Subtracting 0 from 40 leaves us with 40.
Fetch the next digit (5) from the dividend, attach it to 40 and continue: 405 / 90

On to step 3:
The number 90 fits into 405 4 times, leaving a remainder of 45.
The next digit of our result is 4. 
Result so far: 4.0
The remainder is 45 after subtracting 360 from 405.
Append the next digit (0) from the dividend to 45 and continue with: 450 / 90

On to step 4:
The number 90 fits into 450 5 times, leaving a remainder of 0.
Write down 5 as next digit of the result. 
Result so far: 45.0
Deduct 450 from 450 and we're left with 0.
Append the next digit (8) from the dividend to 0 and continue with: 8 / 90

Advancing to step 5:
When dividing 8 by 90, we get 0 with a remainder of 8.
Put 0 as the next digit of the answer. 
Result so far: 450.0
Deduct 0 from 8 and we're left with 8.
Bring next digit (9) of the dividend behind the 8 and repeat the process: 89 / 90

On to step 6:
The number 90 fits into 89 0 times, leaving a remainder of 89.
Record the quotient 0 as the next digit in the result. 
Result so far: 4500.0
Subtract 0 from 89 to get 89.
Since there are no more digits in the dividend, we add a zero to the remainder making it 890, and continue the process.

On to step 7:
When dividing 890 by 90, we get 9 with a remainder of 80.
Write down 9 as next digit of the result. 
Result so far: 4500.9
Subtract 810 from 890 to get 80.
Since there are no more digits in the dividend, we add a zero to the remainder making it 800, and continue the process.

Going ahead to step 8:
90 can be fit into 800 8 times, resulting in a remainder of 80.
Use 8 as the next digit of our solution. 
Result so far: 4500.98
The remainder is 80 after subtracting 720 from 800.
Since there are no more digits in the dividend, we add a zero to the remainder making it 800, and continue the process.

Step 9:
If we divide 800 by 90, we get 8 and a remainder of 80.
The number 8 becomes the next digit in our result. 
Result so far: 4500.988
If we subtract 720 from 800, we get 80.
Since there are no more digits in the dividend, we add a zero to the remainder making it 800, and continue the process.

The final outcome is 4500.988, with a leftover of 0.008.