We look at the division of 91337462 by 646 
The aim is to understand the frequency of 646 in 91337462.

On to step 1:
646 can be fit into 9 0 times, resulting in a remainder of 9.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
The remainder is 9 after subtracting 0 from 9.
Include the next digit (1) from the dividend after 9, then repeat: 91 / 646

Let's proceed to step 2:
If we divide 91 by 646, we get 0 and a remainder of 91.
Write down 0 as next digit of the result. 
Result so far: 0.0
Deduct 0 from 91 and we're left with 91.
Append the next digit (3) from the dividend to 91 and continue with: 913 / 646

On to step 3:
646 can be fit into 913 1 times, resulting in a remainder of 267.
Write down 1 as next digit of the result. 
Result so far: 1.0
Subtracting 646 from 913 leaves us with 267.
Fetch the next digit (3) from the dividend, attach it to 267 and continue: 2673 / 646

Advancing to step 4:
646 goes into 2673 4 times with a remainder of 89.
Record the quotient 4 as the next digit in the result. 
Result so far: 14.0
If we subtract 2584 from 2673, we get 89.
Include the next digit (7) from the dividend after 89, then repeat: 897 / 646

Going ahead to step 5:
897 divided by 646 is 1 with a remainder of 251.
The number 1 becomes the next digit in our result. 
Result so far: 141.0
If we take 646 away from 897, we end up with 251.
Include the next digit (4) from the dividend after 251, then repeat: 2514 / 646

Moving on to step 6:
2514 divided by 646 is 3 with a remainder of 576.
The number 3 becomes the next digit in our result. 
Result so far: 1413.0
The remainder is 576 after subtracting 1938 from 2514.
Append the next digit (6) from the dividend to 576 and continue with: 5766 / 646

Advancing to step 7:
646 can be fit into 5766 8 times, resulting in a remainder of 598.
The next digit of our result is 8. 
Result so far: 14138.0
If we subtract 5168 from 5766, we get 598.
Append the next digit (2) from the dividend to 598 and continue with: 5982 / 646

Advancing to step 8:
646 can be fit into 5982 9 times, resulting in a remainder of 168.
Put 9 as the next digit of the answer. 
Result so far: 141389.0
Deduct 5814 from 5982 and we're left with 168.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1680, and continue the process.

On to step 9:
1680 divided by 646 is 2 with a remainder of 388.
Use 2 as the next digit of our solution. 
Result so far: 141389.2
If we take 1292 away from 1680, we end up with 388.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3880, and continue the process.

Moving on to step 10:
3880 divided by 646 is 6 with a remainder of 4.
Write down 6 as next digit of the result. 
Result so far: 141389.26
If we take 3876 away from 3880, we end up with 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Moving on to step 11:
The number 646 fits into 40 0 times, leaving a remainder of 40.
Record the quotient 0 as the next digit in the result. 
Result so far: 141389.26
Deduct 0 from 40 and we're left with 40.
Since there are no more digits in the dividend, we add a zero to the remainder making it 400, and continue the process.

Let's proceed to step 12:
The number 646 fits into 400 0 times, leaving a remainder of 400.
Write down 0 as next digit of the result. 
Result so far: 141389.26
If we subtract 0 from 400, we get 400.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4000, and continue the process.

After the division, we end up with 141389.26 and a remainder of 0.004.