216419 ÷ 90 
The aim is to understand the frequency of 90 in 216419.

Advancing to step 1:
If we divide 2 by 90, we get 0 and a remainder of 2.
Use 0 as the next digit of our solution. 
Result so far: 0.0
If we take 0 away from 2, we end up with 2.
Append the next digit (1) from the dividend to 2 and continue with: 21 / 90

Advancing to step 2:
The number 90 fits into 21 0 times, leaving a remainder of 21.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Deduct 0 from 21 and we're left with 21.
Grab the next digit (6) from the dividend, add it to 21, then carry on: 216 / 90

Step 3:
90 goes into 216 2 times with a remainder of 36.
Record the quotient 2 as the next digit in the result. 
Result so far: 2.0
The remainder is 36 after subtracting 180 from 216.
Fetch the next digit (4) from the dividend, attach it to 36 and continue: 364 / 90

Let's proceed to step 4:
364 divided by 90 is 4 with a remainder of 4.
The next digit of our result is 4. 
Result so far: 24.0
Deduct 360 from 364 and we're left with 4.
Take the next digit (1) from the dividend and append it to 4, then repeat: 41 / 90

On to step 5:
If we divide 41 by 90, we get 0 and a remainder of 41.
Use 0 as the next digit of our solution. 
Result so far: 240.0
Subtract 0 from 41 to get 41.
Fetch the next digit (9) from the dividend, attach it to 41 and continue: 419 / 90

Step 6:
When dividing 419 by 90, we get 4 with a remainder of 59.
Record the quotient 4 as the next digit in the result. 
Result so far: 2404.0
Deduct 360 from 419 and we're left with 59.
Since there are no more digits in the dividend, we add a zero to the remainder making it 590, and continue the process.

On to step 7:
90 goes into 590 6 times with a remainder of 50.
The next digit of our result is 6. 
Result so far: 2404.6
Deduct 540 from 590 and we're left 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:
90 can be fit into 500 5 times, resulting in a remainder of 50.
Record the quotient 5 as the next digit in the result. 
Result so far: 2404.65
Subtracting 450 from 500 leaves us 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:
90 goes into 500 5 times with a remainder of 50.
The number 5 becomes the next digit in our result. 
Result so far: 2404.655
Subtracting 450 from 500 leaves us 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 2404.655 with a remainder of 0.005.