We're dividing 13309740 by 645 
The aim is to understand the frequency of 645 in 13309740.

On to step 1:
The number 645 fits into 1 0 times, leaving a remainder of 1.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtract 0 from 1 to get 1.
Bring next digit (3) of the dividend behind the 1 and repeat the process: 13 / 645

Moving on to step 2:
The number 645 fits into 13 0 times, leaving a remainder of 13.
The next digit of our result is 0. 
Result so far: 0.0
The remainder is 13 after subtracting 0 from 13.
Include the next digit (3) from the dividend after 13, then repeat: 133 / 645

Let's proceed to step 3:
If we divide 133 by 645, we get 0 and a remainder of 133.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
The remainder is 133 after subtracting 0 from 133.
Grab the next digit (0) from the dividend, add it to 133, then carry on: 1330 / 645

Step 4:
1330 divided by 645 is 2 with a remainder of 40.
Use 2 as the next digit of our solution. 
Result so far: 2.0
Subtracting 1290 from 1330 leaves us with 40.
Grab the next digit (9) from the dividend, add it to 40, then carry on: 409 / 645

Going ahead to step 5:
The number 645 fits into 409 0 times, leaving a remainder of 409.
The next digit of our result is 0. 
Result so far: 20.0
If we subtract 0 from 409, we get 409.
Bring next digit (7) of the dividend behind the 409 and repeat the process: 4097 / 645

Let's proceed to step 6:
645 goes into 4097 6 times with a remainder of 227.
The next digit of our result is 6. 
Result so far: 206.0
If we take 3870 away from 4097, we end up with 227.
Fetch the next digit (4) from the dividend, attach it to 227 and continue: 2274 / 645

Let's proceed to step 7:
645 goes into 2274 3 times with a remainder of 339.
Use 3 as the next digit of our solution. 
Result so far: 2063.0
Deduct 1935 from 2274 and we're left with 339.
Fetch the next digit (0) from the dividend, attach it to 339 and continue: 3390 / 645

Advancing to step 8:
If we divide 3390 by 645, we get 5 and a remainder of 165.
Record the quotient 5 as the next digit in the result. 
Result so far: 20635.0
If we subtract 3225 from 3390, we get 165.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1650, and continue the process.

Let's proceed to step 9:
645 goes into 1650 2 times with a remainder of 360.
The next digit of our result is 2. 
Result so far: 20635.2
Subtract 1290 from 1650 to get 360.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3600, and continue the process.

Advancing to step 10:
645 goes into 3600 5 times with a remainder of 375.
Write down 5 as next digit of the result. 
Result so far: 20635.25
Subtracting 3225 from 3600 leaves us with 375.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3750, and continue the process.

Going ahead to step 11:
3750 divided by 645 is 5 with a remainder of 525.
The next digit of our result is 5. 
Result so far: 20635.255
Subtract 3225 from 3750 to get 525.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5250, and continue the process.

Our division results in 20635.255 with a remaining 0.0525.