We're dividing 40487589 by 645 
The aim is to understand the frequency of 645 in 40487589.

Step 1:
When dividing 4 by 645, we get 0 with a remainder of 4.
Write down 0 as next digit of the result. 
Result so far: 0.0
If we subtract 0 from 4, we get 4.
Take the next digit (0) from the dividend and append it to 4, then repeat: 40 / 645

Advancing to step 2:
The number 645 fits into 40 0 times, leaving a remainder of 40.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Deduct 0 from 40 and we're left with 40.
Append the next digit (4) from the dividend to 40 and continue with: 404 / 645

Advancing to step 3:
645 can be fit into 404 0 times, resulting in a remainder of 404.
Use 0 as the next digit of our solution. 
Result so far: 0.0
If we take 0 away from 404, we end up with 404.
Grab the next digit (8) from the dividend, add it to 404, then carry on: 4048 / 645

Step 4:
4048 divided by 645 is 6 with a remainder of 178.
The next digit of our result is 6. 
Result so far: 6.0
Subtracting 3870 from 4048 leaves us with 178.
Append the next digit (7) from the dividend to 178 and continue with: 1787 / 645

Step 5:
When dividing 1787 by 645, we get 2 with a remainder of 497.
Record the quotient 2 as the next digit in the result. 
Result so far: 62.0
If we take 1290 away from 1787, we end up with 497.
Append the next digit (5) from the dividend to 497 and continue with: 4975 / 645

On to step 6:
When dividing 4975 by 645, we get 7 with a remainder of 460.
Put 7 as the next digit of the answer. 
Result so far: 627.0
Subtracting 4515 from 4975 leaves us with 460.
Fetch the next digit (8) from the dividend, attach it to 460 and continue: 4608 / 645

Going ahead to step 7:
If we divide 4608 by 645, we get 7 and a remainder of 93.
The number 7 becomes the next digit in our result. 
Result so far: 6277.0
Subtracting 4515 from 4608 leaves us with 93.
Append the next digit (9) from the dividend to 93 and continue with: 939 / 645

On to step 8:
645 goes into 939 1 times with a remainder of 294.
Write down 1 as next digit of the result. 
Result so far: 62771.0
The remainder is 294 after subtracting 645 from 939.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2940, and continue the process.

Going ahead to step 9:
2940 divided by 645 is 4 with a remainder of 360.
The number 4 becomes the next digit in our result. 
Result so far: 62771.4
The remainder is 360 after subtracting 2580 from 2940.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3600, and continue the process.

Step 10:
645 goes into 3600 5 times with a remainder of 375.
Record the quotient 5 as the next digit in the result. 
Result so far: 62771.45
If we take 3225 away from 3600, we end up 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.

Moving on to step 11:
When dividing 3750 by 645, we get 5 with a remainder of 525.
Record the quotient 5 as the next digit in the result. 
Result so far: 62771.455
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.

The quotient of the division is 62771.455, and the remainder is 0.0525.