28136432 divided by 645 
The aim is to understand the frequency of 645 in 28136432.

On to step 1:
When dividing 2 by 645, we get 0 with a remainder of 2.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Deduct 0 from 2 and we're left with 2.
Include the next digit (8) from the dividend after 2, then repeat: 28 / 645

Step 2:
The number 645 fits into 28 0 times, leaving a remainder of 28.
Write down 0 as next digit of the result. 
Result so far: 0.0
Subtract 0 from 28 to get 28.
Grab the next digit (1) from the dividend, add it to 28, then carry on: 281 / 645

Moving on to step 3:
281 divided by 645 is 0 with a remainder of 281.
Put 0 as the next digit of the answer. 
Result so far: 0.0
The remainder is 281 after subtracting 0 from 281.
Bring next digit (3) of the dividend behind the 281 and repeat the process: 2813 / 645

Advancing to step 4:
645 can be fit into 2813 4 times, resulting in a remainder of 233.
Record the quotient 4 as the next digit in the result. 
Result so far: 4.0
If we take 2580 away from 2813, we end up with 233.
Include the next digit (6) from the dividend after 233, then repeat: 2336 / 645

Let's proceed to step 5:
If we divide 2336 by 645, we get 3 and a remainder of 401.
The next digit of our result is 3. 
Result so far: 43.0
Deduct 1935 from 2336 and we're left with 401.
Append the next digit (4) from the dividend to 401 and continue with: 4014 / 645

On to step 6:
When dividing 4014 by 645, we get 6 with a remainder of 144.
Record the quotient 6 as the next digit in the result. 
Result so far: 436.0
Subtract 3870 from 4014 to get 144.
Take the next digit (3) from the dividend and append it to 144, then repeat: 1443 / 645

Let's proceed to step 7:
1443 divided by 645 is 2 with a remainder of 153.
The next digit of our result is 2. 
Result so far: 4362.0
Subtracting 1290 from 1443 leaves us with 153.
Fetch the next digit (2) from the dividend, attach it to 153 and continue: 1532 / 645

Advancing to step 8:
645 can be fit into 1532 2 times, resulting in a remainder of 242.
The number 2 becomes the next digit in our result. 
Result so far: 43622.0
Deduct 1290 from 1532 and we're left with 242.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2420, and continue the process.

Advancing to step 9:
The number 645 fits into 2420 3 times, leaving a remainder of 485.
Use 3 as the next digit of our solution. 
Result so far: 43622.3
Deduct 1935 from 2420 and we're left with 485.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4850, and continue the process.

Going ahead to step 10:
645 goes into 4850 7 times with a remainder of 335.
Put 7 as the next digit of the answer. 
Result so far: 43622.37
Subtracting 4515 from 4850 leaves us with 335.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3350, and continue the process.

Let's proceed to step 11:
When dividing 3350 by 645, we get 5 with a remainder of 125.
The number 5 becomes the next digit in our result. 
Result so far: 43622.375
The remainder is 125 after subtracting 3225 from 3350.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1250, and continue the process.

Step 12:
If we divide 1250 by 645, we get 1 and a remainder of 605.
Use 1 as the next digit of our solution. 
Result so far: 43622.3751
Subtracting 645 from 1250 leaves us with 605.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6050, and continue the process.

Going ahead to step 13:
When dividing 6050 by 645, we get 9 with a remainder of 245.
Write down 9 as next digit of the result. 
Result so far: 43622.37519
If we subtract 5805 from 6050, we get 245.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2450, and continue the process.

Advancing to step 14:
2450 divided by 645 is 3 with a remainder of 515.
Record the quotient 3 as the next digit in the result. 
Result so far: 43622.375193
Subtracting 1935 from 2450 leaves us with 515.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5150, and continue the process.

Advancing to step 15:
645 can be fit into 5150 7 times, resulting in a remainder of 635.
The number 7 becomes the next digit in our result. 
Result so far: 43622.3751937
If we subtract 4515 from 5150, we get 635.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6350, and continue the process.

Moving on to step 16:
6350 divided by 645 is 9 with a remainder of 545.
Record the quotient 9 as the next digit in the result. 
Result so far: 43622.37519379
If we take 5805 away from 6350, we end up with 545.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5450, and continue the process.

After the division, we end up with 43622.37519379 and a remainder of 5.45e-07.