521073 ÷ 9 
The aim is to understand the frequency of 9 in 521073.

Let's proceed to step 1:
If we divide 5 by 9, we get 0 and a remainder of 5.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Deduct 0 from 5 and we're left with 5.
Append the next digit (2) from the dividend to 5 and continue with: 52 / 9

Advancing to step 2:
9 goes into 52 5 times with a remainder of 7.
The next digit of our result is 5. 
Result so far: 5.0
If we subtract 45 from 52, we get 7.
Bring next digit (1) of the dividend behind the 7 and repeat the process: 71 / 9

Advancing to step 3:
9 can be fit into 71 7 times, resulting in a remainder of 8.
Record the quotient 7 as the next digit in the result. 
Result so far: 57.0
Subtracting 63 from 71 leaves us with 8.
Take the next digit (0) from the dividend and append it to 8, then repeat: 80 / 9

Step 4:
80 divided by 9 is 8 with a remainder of 8.
Use 8 as the next digit of our solution. 
Result so far: 578.0
Deduct 72 from 80 and we're left with 8.
Grab the next digit (7) from the dividend, add it to 8, then carry on: 87 / 9

Let's proceed to step 5:
When dividing 87 by 9, we get 9 with a remainder of 6.
Use 9 as the next digit of our solution. 
Result so far: 5789.0
The remainder is 6 after subtracting 81 from 87.
Grab the next digit (3) from the dividend, add it to 6, then carry on: 63 / 9

Step 6:
If we divide 63 by 9, we get 7 and a remainder of 0.
The number 7 becomes the next digit in our result. 
Result so far: 57897.0
If we subtract 63 from 63, we 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.

Step 7:
If we divide 0 by 9, we get 0 and a remainder of 0.
Put 0 as the next digit of the answer. 
Result so far: 57897.0
The remainder is 0 after subtracting 0 from 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 8:
9 goes into 0 0 times with a remainder of 0.
The next digit of our result is 0. 
Result so far: 57897.0
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.

After the division, we end up with 57897.0 and a remainder of 0.0.