7643109 ÷ 551 
The aim is to understand the frequency of 551 in 7643109.

Going ahead to step 1:
If we divide 7 by 551, we get 0 and a remainder of 7.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
The remainder is 7 after subtracting 0 from 7.
Append the next digit (6) from the dividend to 7 and continue with: 76 / 551

Let's proceed to step 2:
551 can be fit into 76 0 times, resulting in a remainder of 76.
Write down 0 as next digit of the result. 
Result so far: 0.0
If we subtract 0 from 76, we get 76.
Append the next digit (4) from the dividend to 76 and continue with: 764 / 551

On to step 3:
551 can be fit into 764 1 times, resulting in a remainder of 213.
Put 1 as the next digit of the answer. 
Result so far: 1.0
If we subtract 551 from 764, we get 213.
Append the next digit (3) from the dividend to 213 and continue with: 2133 / 551

Step 4:
551 goes into 2133 3 times with a remainder of 480.
The number 3 becomes the next digit in our result. 
Result so far: 13.0
Deduct 1653 from 2133 and we're left with 480.
Bring next digit (1) of the dividend behind the 480 and repeat the process: 4801 / 551

On to step 5:
551 can be fit into 4801 8 times, resulting in a remainder of 393.
Use 8 as the next digit of our solution. 
Result so far: 138.0
Subtracting 4408 from 4801 leaves us with 393.
Fetch the next digit (0) from the dividend, attach it to 393 and continue: 3930 / 551

Moving on to step 6:
551 goes into 3930 7 times with a remainder of 73.
The number 7 becomes the next digit in our result. 
Result so far: 1387.0
If we subtract 3857 from 3930, we get 73.
Take the next digit (9) from the dividend and append it to 73, then repeat: 739 / 551

Going ahead to step 7:
551 goes into 739 1 times with a remainder of 188.
Use 1 as the next digit of our solution. 
Result so far: 13871.0
If we take 551 away from 739, we end up with 188.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1880, and continue the process.

Step 8:
The number 551 fits into 1880 3 times, leaving a remainder of 227.
Use 3 as the next digit of our solution. 
Result so far: 13871.3
Subtracting 1653 from 1880 leaves us with 227.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2270, and continue the process.

Advancing to step 9:
If we divide 2270 by 551, we get 4 and a remainder of 66.
Write down 4 as next digit of the result. 
Result so far: 13871.34
Deduct 2204 from 2270 and we're left with 66.
Since there are no more digits in the dividend, we add a zero to the remainder making it 660, and continue the process.

On to step 10:
The number 551 fits into 660 1 times, leaving a remainder of 109.
Record the quotient 1 as the next digit in the result. 
Result so far: 13871.341
Subtracting 551 from 660 leaves us with 109.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1090, and continue the process.

Moving on to step 11:
551 can be fit into 1090 1 times, resulting in a remainder of 539.
Write down 1 as next digit of the result. 
Result so far: 13871.3411
Subtracting 551 from 1090 leaves us with 539.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5390, and continue the process.

After the division, we end up with 13871.3411 and a remainder of 0.00539.