72878166 divided by 90 
The aim is to understand the frequency of 90 in 72878166.

Advancing to step 1:
The number 90 fits into 7 0 times, leaving a remainder of 7.
Put 0 as the next digit of the answer. 
Result so far: 0.0
The remainder is 7 after subtracting 0 from 7.
Bring next digit (2) of the dividend behind the 7 and repeat the process: 72 / 90

Step 2:
If we divide 72 by 90, we get 0 and a remainder of 72.
The next digit of our result is 0. 
Result so far: 0.0
Subtract 0 from 72 to get 72.
Take the next digit (8) from the dividend and append it to 72, then repeat: 728 / 90

Going ahead to step 3:
If we divide 728 by 90, we get 8 and a remainder of 8.
The next digit of our result is 8. 
Result so far: 8.0
If we subtract 720 from 728, we get 8.
Grab the next digit (7) from the dividend, add it to 8, then carry on: 87 / 90

Moving on to step 4:
If we divide 87 by 90, we get 0 and a remainder of 87.
The number 0 becomes the next digit in our result. 
Result so far: 80.0
Deduct 0 from 87 and we're left with 87.
Fetch the next digit (8) from the dividend, attach it to 87 and continue: 878 / 90

On to step 5:
The number 90 fits into 878 9 times, leaving a remainder of 68.
Record the quotient 9 as the next digit in the result. 
Result so far: 809.0
The remainder is 68 after subtracting 810 from 878.
Bring next digit (1) of the dividend behind the 68 and repeat the process: 681 / 90

Advancing to step 6:
The number 90 fits into 681 7 times, leaving a remainder of 51.
Put 7 as the next digit of the answer. 
Result so far: 8097.0
The remainder is 51 after subtracting 630 from 681.
Grab the next digit (6) from the dividend, add it to 51, then carry on: 516 / 90

Moving on to step 7:
90 goes into 516 5 times with a remainder of 66.
Use 5 as the next digit of our solution. 
Result so far: 80975.0
If we take 450 away from 516, we end up with 66.
Append the next digit (6) from the dividend to 66 and continue with: 666 / 90

Let's proceed to step 8:
When dividing 666 by 90, we get 7 with a remainder of 36.
The number 7 becomes the next digit in our result. 
Result so far: 809757.0
If we subtract 630 from 666, we get 36.
Since there are no more digits in the dividend, we add a zero to the remainder making it 360, and continue the process.

Going ahead to step 9:
90 can be fit into 360 4 times, resulting in a remainder of 0.
The next digit of our result is 4. 
Result so far: 809757.4
If we take 360 away from 360, we end up 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.

Let's proceed to step 10:
The number 90 fits into 0 0 times, leaving a remainder of 0.
Put 0 as the next digit of the answer. 
Result so far: 809757.4
If we take 0 away from 0, we end up 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.

Going ahead to step 11:
The number 90 fits into 0 0 times, leaving a remainder of 0.
The number 0 becomes the next digit in our result. 
Result so far: 809757.4
Deduct 0 from 0 and we're left 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.

The quotient of the division is 809757.4, and the remainder is 0.0.