We look at the division of 69979672 by 646 
The aim is to understand the frequency of 646 in 69979672.

Advancing to step 1:
If we divide 6 by 646, we get 0 and a remainder of 6.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we take 0 away from 6, we end up with 6.
Bring next digit (9) of the dividend behind the 6 and repeat the process: 69 / 646

On to step 2:
The number 646 fits into 69 0 times, leaving a remainder of 69.
The next digit of our result is 0. 
Result so far: 0.0
The remainder is 69 after subtracting 0 from 69.
Include the next digit (9) from the dividend after 69, then repeat: 699 / 646

Advancing to step 3:
646 goes into 699 1 times with a remainder of 53.
Put 1 as the next digit of the answer. 
Result so far: 1.0
Deduct 646 from 699 and we're left with 53.
Include the next digit (7) from the dividend after 53, then repeat: 537 / 646

Advancing to step 4:
The number 646 fits into 537 0 times, leaving a remainder of 537.
The number 0 becomes the next digit in our result. 
Result so far: 10.0
Deduct 0 from 537 and we're left with 537.
Take the next digit (9) from the dividend and append it to 537, then repeat: 5379 / 646

Advancing to step 5:
646 goes into 5379 8 times with a remainder of 211.
Write down 8 as next digit of the result. 
Result so far: 108.0
Deduct 5168 from 5379 and we're left with 211.
Fetch the next digit (6) from the dividend, attach it to 211 and continue: 2116 / 646

Let's proceed to step 6:
If we divide 2116 by 646, we get 3 and a remainder of 178.
Record the quotient 3 as the next digit in the result. 
Result so far: 1083.0
Deduct 1938 from 2116 and we're left with 178.
Include the next digit (7) from the dividend after 178, then repeat: 1787 / 646

Let's proceed to step 7:
1787 divided by 646 is 2 with a remainder of 495.
The next digit of our result is 2. 
Result so far: 10832.0
If we subtract 1292 from 1787, we get 495.
Include the next digit (2) from the dividend after 495, then repeat: 4952 / 646

Let's proceed to step 8:
When dividing 4952 by 646, we get 7 with a remainder of 430.
The number 7 becomes the next digit in our result. 
Result so far: 108327.0
If we subtract 4522 from 4952, we get 430.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4300, and continue the process.

Advancing to step 9:
When dividing 4300 by 646, we get 6 with a remainder of 424.
Put 6 as the next digit of the answer. 
Result so far: 108327.6
If we take 3876 away from 4300, we end up with 424.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4240, and continue the process.

Let's proceed to step 10:
When dividing 4240 by 646, we get 6 with a remainder of 364.
The number 6 becomes the next digit in our result. 
Result so far: 108327.66
Subtracting 3876 from 4240 leaves us with 364.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3640, and continue the process.

After the division, we end up with 108327.66 and a remainder of 0.364.