We look at the division of 84690575 by 645 
The aim is to understand the frequency of 645 in 84690575.

Step 1:
645 goes into 8 0 times with a remainder of 8.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
If we subtract 0 from 8, we get 8.
Include the next digit (4) from the dividend after 8, then repeat: 84 / 645

Advancing to step 2:
645 can be fit into 84 0 times, resulting in a remainder of 84.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Deduct 0 from 84 and we're left with 84.
Append the next digit (6) from the dividend to 84 and continue with: 846 / 645

Let's proceed to step 3:
645 goes into 846 1 times with a remainder of 201.
Record the quotient 1 as the next digit in the result. 
Result so far: 1.0
Subtracting 645 from 846 leaves us with 201.
Include the next digit (9) from the dividend after 201, then repeat: 2019 / 645

Going ahead to step 4:
645 goes into 2019 3 times with a remainder of 84.
Put 3 as the next digit of the answer. 
Result so far: 13.0
If we take 1935 away from 2019, we end up with 84.
Bring next digit (0) of the dividend behind the 84 and repeat the process: 840 / 645

Going ahead to step 5:
The number 645 fits into 840 1 times, leaving a remainder of 195.
Record the quotient 1 as the next digit in the result. 
Result so far: 131.0
Deduct 645 from 840 and we're left with 195.
Include the next digit (5) from the dividend after 195, then repeat: 1955 / 645

Going ahead to step 6:
The number 645 fits into 1955 3 times, leaving a remainder of 20.
Record the quotient 3 as the next digit in the result. 
Result so far: 1313.0
The remainder is 20 after subtracting 1935 from 1955.
Append the next digit (7) from the dividend to 20 and continue with: 207 / 645

Going ahead to step 7:
645 can be fit into 207 0 times, resulting in a remainder of 207.
The number 0 becomes the next digit in our result. 
Result so far: 13130.0
Deduct 0 from 207 and we're left with 207.
Fetch the next digit (5) from the dividend, attach it to 207 and continue: 2075 / 645

Let's proceed to step 8:
If we divide 2075 by 645, we get 3 and a remainder of 140.
Put 3 as the next digit of the answer. 
Result so far: 131303.0
Deduct 1935 from 2075 and we're left with 140.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1400, and continue the process.

Moving on to step 9:
645 goes into 1400 2 times with a remainder of 110.
The next digit of our result is 2. 
Result so far: 131303.2
If we subtract 1290 from 1400, we get 110.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1100, and continue the process.

On to step 10:
If we divide 1100 by 645, we get 1 and a remainder of 455.
Record the quotient 1 as the next digit in the result. 
Result so far: 131303.21
The remainder is 455 after subtracting 645 from 1100.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4550, and continue the process.

Going ahead to step 11:
645 can be fit into 4550 7 times, resulting in a remainder of 35.
Write down 7 as next digit of the result. 
Result so far: 131303.217
Subtracting 4515 from 4550 leaves us with 35.
Since there are no more digits in the dividend, we add a zero to the remainder making it 350, and continue the process.

On to step 12:
If we divide 350 by 645, we get 0 and a remainder of 350.
Record the quotient 0 as the next digit in the result. 
Result so far: 131303.217
If we subtract 0 from 350, we get 350.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3500, and continue the process.

Step 13:
If we divide 3500 by 645, we get 5 and a remainder of 275.
Write down 5 as next digit of the result. 
Result so far: 131303.21705
Subtract 3225 from 3500 to get 275.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2750, and continue the process.

Let's proceed to step 14:
The number 645 fits into 2750 4 times, leaving a remainder of 170.
Record the quotient 4 as the next digit in the result. 
Result so far: 131303.217054
If we take 2580 away from 2750, we end up with 170.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1700, and continue the process.

Advancing to step 15:
When dividing 1700 by 645, we get 2 with a remainder of 410.
The number 2 becomes the next digit in our result. 
Result so far: 131303.2170542
Subtracting 1290 from 1700 leaves us with 410.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4100, and continue the process.

Let's proceed to step 16:
If we divide 4100 by 645, we get 6 and a remainder of 230.
The next digit of our result is 6. 
Result so far: 131303.21705426
Deduct 3870 from 4100 and we're left with 230.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2300, and continue the process.

In conclusion, the division gives 131303.21705426 with a balance of 2.3e-07.