We look at the division of 397440 by 90 
The aim is to understand the frequency of 90 in 397440.

Let's proceed to step 1:
90 goes into 3 0 times with a remainder of 3.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtract 0 from 3 to get 3.
Fetch the next digit (9) from the dividend, attach it to 3 and continue: 39 / 90

Going ahead to step 2:
90 goes into 39 0 times with a remainder of 39.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we take 0 away from 39, we end up with 39.
Fetch the next digit (7) from the dividend, attach it to 39 and continue: 397 / 90

Going ahead to step 3:
397 divided by 90 is 4 with a remainder of 37.
Use 4 as the next digit of our solution. 
Result so far: 4.0
If we take 360 away from 397, we end up with 37.
Grab the next digit (4) from the dividend, add it to 37, then carry on: 374 / 90

Let's proceed to step 4:
When dividing 374 by 90, we get 4 with a remainder of 14.
Put 4 as the next digit of the answer. 
Result so far: 44.0
If we subtract 360 from 374, we get 14.
Bring next digit (4) of the dividend behind the 14 and repeat the process: 144 / 90

On to step 5:
When dividing 144 by 90, we get 1 with a remainder of 54.
Write down 1 as next digit of the result. 
Result so far: 441.0
If we take 90 away from 144, we end up with 54.
Fetch the next digit (0) from the dividend, attach it to 54 and continue: 540 / 90

Step 6:
When dividing 540 by 90, we get 6 with a remainder of 0.
The number 6 becomes the next digit in our result. 
Result so far: 4416.0
Subtracting 540 from 540 leaves us with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Step 7:
90 goes into 0 0 times with a remainder of 0.
The next digit of our result is 0. 
Result so far: 4416.0
Subtracting 0 from 0 leaves us with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Moving on to step 8:
90 goes into 0 0 times with a remainder of 0.
Use 0 as the next digit of our solution. 
Result so far: 4416.0
Subtract 0 from 0 to get 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Our division results in 4416.0 with a remaining 0.0.