We look at the division of 407521 by 9 
The aim is to understand the frequency of 9 in 407521.

Moving on to step 1:
9 goes into 4 0 times with a remainder of 4.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Deduct 0 from 4 and we're left with 4.
Include the next digit (0) from the dividend after 4, then repeat: 40 / 9

Going ahead to step 2:
9 goes into 40 4 times with a remainder of 4.
The next digit of our result is 4. 
Result so far: 4.0
If we take 36 away from 40, we end up with 4.
Append the next digit (7) from the dividend to 4 and continue with: 47 / 9

Going ahead to step 3:
9 goes into 47 5 times with a remainder of 2.
Write down 5 as next digit of the result. 
Result so far: 45.0
Subtracting 45 from 47 leaves us with 2.
Take the next digit (5) from the dividend and append it to 2, then repeat: 25 / 9

Going ahead to step 4:
The number 9 fits into 25 2 times, leaving a remainder of 7.
The number 2 becomes the next digit in our result. 
Result so far: 452.0
The remainder is 7 after subtracting 18 from 25.
Take the next digit (2) from the dividend and append it to 7, then repeat: 72 / 9

Advancing to step 5:
If we divide 72 by 9, we get 8 and a remainder of 0.
Record the quotient 8 as the next digit in the result. 
Result so far: 4528.0
If we subtract 72 from 72, we get 0.
Include the next digit (1) from the dividend after 0, then repeat: 1 / 9

Going ahead to step 6:
9 goes into 1 0 times with a remainder of 1.
Write down 0 as next digit of the result. 
Result so far: 45280.0
The remainder is 1 after subtracting 0 from 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Going ahead to step 7:
If we divide 10 by 9, we get 1 and a remainder of 1.
Put 1 as the next digit of the answer. 
Result so far: 45280.1
If we take 9 away from 10, we end up with 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Advancing to step 8:
The number 9 fits into 10 1 times, leaving a remainder of 1.
Record the quotient 1 as the next digit in the result. 
Result so far: 45280.11
Subtract 9 from 10 to get 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Our division results in 45280.11 with a remaining 0.001.