We divide 75085561 by 645
The aim is to understand the frequency of 645 in 75085561.

Let's proceed to step 1:
7 divided by 645 is 0 with a remainder of 7.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtract 0 from 7 to get 7.
Take the next digit (5) from the dividend and append it to 7, then repeat: 75 / 645

Advancing to step 2:
75 divided by 645 is 0 with a remainder of 75.
Write down 0 as next digit of the result. 
Result so far: 0.0
Deduct 0 from 75 and we're left with 75.
Take the next digit (0) from the dividend and append it to 75, then repeat: 750 / 645

Moving on to step 3:
645 goes into 750 1 times with a remainder of 105.
Use 1 as the next digit of our solution. 
Result so far: 1.0
If we take 645 away from 750, we end up with 105.
Fetch the next digit (8) from the dividend, attach it to 105 and continue: 1058 / 645

Moving on to step 4:
645 goes into 1058 1 times with a remainder of 413.
The number 1 becomes the next digit in our result. 
Result so far: 11.0
Subtract 645 from 1058 to get 413.
Fetch the next digit (5) from the dividend, attach it to 413 and continue: 4135 / 645

Let's proceed to step 5:
The number 645 fits into 4135 6 times, leaving a remainder of 265.
The number 6 becomes the next digit in our result. 
Result so far: 116.0
If we subtract 3870 from 4135, we get 265.
Grab the next digit (5) from the dividend, add it to 265, then carry on: 2655 / 645

Let's proceed to step 6:
2655 divided by 645 is 4 with a remainder of 75.
Record the quotient 4 as the next digit in the result. 
Result so far: 1164.0
Subtract 2580 from 2655 to get 75.
Fetch the next digit (6) from the dividend, attach it to 75 and continue: 756 / 645

Advancing to step 7:
The number 645 fits into 756 1 times, leaving a remainder of 111.
The number 1 becomes the next digit in our result. 
Result so far: 11641.0
If we subtract 645 from 756, we get 111.
Bring next digit (1) of the dividend behind the 111 and repeat the process: 1111 / 645

Moving on to step 8:
645 can be fit into 1111 1 times, resulting in a remainder of 466.
Use 1 as the next digit of our solution. 
Result so far: 116411.0
Deduct 645 from 1111 and we're left with 466.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4660, and continue the process.

On to step 9:
If we divide 4660 by 645, we get 7 and a remainder of 145.
Write down 7 as next digit of the result. 
Result so far: 116411.7
If we subtract 4515 from 4660, we get 145.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1450, and continue the process.

Let's proceed to step 10:
If we divide 1450 by 645, we get 2 and a remainder of 160.
The next digit of our result is 2. 
Result so far: 116411.72
If we take 1290 away from 1450, we end up with 160.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1600, and continue the process.

On to step 11:
645 goes into 1600 2 times with a remainder of 310.
Put 2 as the next digit of the answer. 
Result so far: 116411.722
Deduct 1290 from 1600 and we're left with 310.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3100, and continue the process.

Our division results in 116411.722 with a remaining 0.031.