We're dividing 52555780 by 645 
The aim is to understand the frequency of 645 in 52555780.

Going ahead to step 1:
5 divided by 645 is 0 with a remainder of 5.
The next digit of our result is 0. 
Result so far: 0.0
Deduct 0 from 5 and we're left with 5.
Grab the next digit (2) from the dividend, add it to 5, then carry on: 52 / 645

Moving on to step 2:
645 goes into 52 0 times with a remainder of 52.
The next digit of our result is 0. 
Result so far: 0.0
Deduct 0 from 52 and we're left with 52.
Append the next digit (5) from the dividend to 52 and continue with: 525 / 645

On to step 3:
The number 645 fits into 525 0 times, leaving a remainder of 525.
The next digit of our result is 0. 
Result so far: 0.0
Deduct 0 from 525 and we're left with 525.
Take the next digit (5) from the dividend and append it to 525, then repeat: 5255 / 645

Step 4:
645 goes into 5255 8 times with a remainder of 95.
Record the quotient 8 as the next digit in the result. 
Result so far: 8.0
The remainder is 95 after subtracting 5160 from 5255.
Take the next digit (5) from the dividend and append it to 95, then repeat: 955 / 645

Let's proceed to step 5:
955 divided by 645 is 1 with a remainder of 310.
Record the quotient 1 as the next digit in the result. 
Result so far: 81.0
The remainder is 310 after subtracting 645 from 955.
Include the next digit (7) from the dividend after 310, then repeat: 3107 / 645

Going ahead to step 6:
The number 645 fits into 3107 4 times, leaving a remainder of 527.
Use 4 as the next digit of our solution. 
Result so far: 814.0
Deduct 2580 from 3107 and we're left with 527.
Append the next digit (8) from the dividend to 527 and continue with: 5278 / 645

Let's proceed to step 7:
If we divide 5278 by 645, we get 8 and a remainder of 118.
The next digit of our result is 8. 
Result so far: 8148.0
Subtract 5160 from 5278 to get 118.
Fetch the next digit (0) from the dividend, attach it to 118 and continue: 1180 / 645

Moving on to step 8:
645 goes into 1180 1 times with a remainder of 535.
Put 1 as the next digit of the answer. 
Result so far: 81481.0
The remainder is 535 after subtracting 645 from 1180.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5350, and continue the process.

Let's proceed to step 9:
645 goes into 5350 8 times with a remainder of 190.
Write down 8 as next digit of the result. 
Result so far: 81481.8
If we take 5160 away from 5350, we end up with 190.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1900, and continue the process.

Let's proceed to step 10:
645 can be fit into 1900 2 times, resulting in a remainder of 610.
Record the quotient 2 as the next digit in the result. 
Result so far: 81481.82
Deduct 1290 from 1900 and we're left with 610.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6100, and continue the process.

Let's proceed to step 11:
645 can be fit into 6100 9 times, resulting in a remainder of 295.
Write down 9 as next digit of the result. 
Result so far: 81481.829
Subtracting 5805 from 6100 leaves us with 295.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2950, and continue the process.

Let's proceed to step 12:
645 can be fit into 2950 4 times, resulting in a remainder of 370.
Write down 4 as next digit of the result. 
Result so far: 81481.8294
The remainder is 370 after subtracting 2580 from 2950.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3700, and continue the process.

Going ahead to step 13:
The number 645 fits into 3700 5 times, leaving a remainder of 475.
Put 5 as the next digit of the answer. 
Result so far: 81481.82945
Subtract 3225 from 3700 to get 475.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4750, and continue the process.

Moving on to step 14:
4750 divided by 645 is 7 with a remainder of 235.
The next digit of our result is 7. 
Result so far: 81481.829457
Subtract 4515 from 4750 to get 235.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2350, and continue the process.

Going ahead to step 15:
When dividing 2350 by 645, we get 3 with a remainder of 415.
Put 3 as the next digit of the answer. 
Result so far: 81481.8294573
Subtract 1935 from 2350 to get 415.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4150, and continue the process.

Moving on to step 16:
If we divide 4150 by 645, we get 6 and a remainder of 280.
The next digit of our result is 6. 
Result so far: 81481.82945736
Subtract 3870 from 4150 to get 280.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2800, and continue the process.

The final outcome is 81481.82945736, with a leftover of 2.8e-07.