91209031 ÷ 73 
The aim is to understand the frequency of 73 in 91209031.

Moving on to step 1:
73 can be fit into 9 0 times, resulting in a remainder of 9.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Subtracting 0 from 9 leaves us with 9.
Append the next digit (1) from the dividend to 9 and continue with: 91 / 73

Advancing to step 2:
If we divide 91 by 73, we get 1 and a remainder of 18.
Put 1 as the next digit of the answer. 
Result so far: 1.0
Subtract 73 from 91 to get 18.
Fetch the next digit (2) from the dividend, attach it to 18 and continue: 182 / 73

Let's proceed to step 3:
When dividing 182 by 73, we get 2 with a remainder of 36.
Write down 2 as next digit of the result. 
Result so far: 12.0
Subtracting 146 from 182 leaves us with 36.
Grab the next digit (0) from the dividend, add it to 36, then carry on: 360 / 73

Let's proceed to step 4:
360 divided by 73 is 4 with a remainder of 68.
The number 4 becomes the next digit in our result. 
Result so far: 124.0
Subtract 292 from 360 to get 68.
Grab the next digit (9) from the dividend, add it to 68, then carry on: 689 / 73

On to step 5:
If we divide 689 by 73, we get 9 and a remainder of 32.
Put 9 as the next digit of the answer. 
Result so far: 1249.0
Subtract 657 from 689 to get 32.
Append the next digit (0) from the dividend to 32 and continue with: 320 / 73

Step 6:
When dividing 320 by 73, we get 4 with a remainder of 28.
The next digit of our result is 4. 
Result so far: 12494.0
Deduct 292 from 320 and we're left with 28.
Fetch the next digit (3) from the dividend, attach it to 28 and continue: 283 / 73

On to step 7:
The number 73 fits into 283 3 times, leaving a remainder of 64.
The next digit of our result is 3. 
Result so far: 124943.0
Deduct 219 from 283 and we're left with 64.
Take the next digit (1) from the dividend and append it to 64, then repeat: 641 / 73

Let's proceed to step 8:
641 divided by 73 is 8 with a remainder of 57.
The number 8 becomes the next digit in our result. 
Result so far: 1249438.0
Subtracting 584 from 641 leaves us with 57.
Since there are no more digits in the dividend, we add a zero to the remainder making it 570, and continue the process.

On to step 9:
If we divide 570 by 73, we get 7 and a remainder of 59.
Record the quotient 7 as the next digit in the result. 
Result so far: 1249438.7
If we subtract 511 from 570, we get 59.
Since there are no more digits in the dividend, we add a zero to the remainder making it 590, and continue the process.

Going ahead to step 10:
If we divide 590 by 73, we get 8 and a remainder of 6.
Write down 8 as next digit of the result. 
Result so far: 1249438.78
Deduct 584 from 590 and we're left with 6.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

Step 11:
When dividing 60 by 73, we get 0 with a remainder of 60.
Record the quotient 0 as the next digit in the result. 
Result so far: 1249438.78
Subtract 0 from 60 to get 60.
Since there are no more digits in the dividend, we add a zero to the remainder making it 600, and continue the process.

Moving on to step 12:
73 can be fit into 600 8 times, resulting in a remainder of 16.
The next digit of our result is 8. 
Result so far: 1249438.7808
The remainder is 16 after subtracting 584 from 600.
Since there are no more digits in the dividend, we add a zero to the remainder making it 160, and continue the process.

Going ahead to step 13:
160 divided by 73 is 2 with a remainder of 14.
Use 2 as the next digit of our solution. 
Result so far: 1249438.78082
The remainder is 14 after subtracting 146 from 160.
Since there are no more digits in the dividend, we add a zero to the remainder making it 140, and continue the process.

Moving on to step 14:
140 divided by 73 is 1 with a remainder of 67.
Write down 1 as next digit of the result. 
Result so far: 1249438.780821
Subtracting 73 from 140 leaves us with 67.
Since there are no more digits in the dividend, we add a zero to the remainder making it 670, and continue the process.

Going ahead to step 15:
73 goes into 670 9 times with a remainder of 13.
Put 9 as the next digit of the answer. 
Result so far: 1249438.7808219
If we take 657 away from 670, we end up with 13.
Since there are no more digits in the dividend, we add a zero to the remainder making it 130, and continue the process.

Going ahead to step 16:
130 divided by 73 is 1 with a remainder of 57.
Put 1 as the next digit of the answer. 
Result so far: 1249438.78082191
Subtracting 73 from 130 leaves us with 57.
Since there are no more digits in the dividend, we add a zero to the remainder making it 570, and continue the process.

The final result is 1249438.78082191 with a remainder of 5.7e-08.