Let's divide 20502840 by 645
Let's see how many times 645 fits into 20502840.

Going ahead to step 1:
The number 645 fits into 2 0 times, leaving a remainder of 2.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
The remainder is 2 after subtracting 0 from 2.
Fetch the next digit (0) from the dividend, attach it to 2 and continue: 20 / 645

Going ahead to step 2:
20 divided by 645 is 0 with a remainder of 20.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Deduct 0 from 20 and we're left with 20.
Bring next digit (5) of the dividend behind the 20 and repeat the process: 205 / 645

Step 3:
The number 645 fits into 205 0 times, leaving a remainder of 205.
Write down 0 as next digit of the result. 
Result so far: 0.0
The remainder is 205 after subtracting 0 from 205.
Take the next digit (0) from the dividend and append it to 205, then repeat: 2050 / 645

Advancing to step 4:
2050 divided by 645 is 3 with a remainder of 115.
Put 3 as the next digit of the answer. 
Result so far: 3.0
Subtract 1935 from 2050 to get 115.
Grab the next digit (2) from the dividend, add it to 115, then carry on: 1152 / 645

Let's proceed to step 5:
645 can be fit into 1152 1 times, resulting in a remainder of 507.
The next digit of our result is 1. 
Result so far: 31.0
If we subtract 645 from 1152, we get 507.
Bring next digit (8) of the dividend behind the 507 and repeat the process: 5078 / 645

Going ahead to step 6:
The number 645 fits into 5078 7 times, leaving a remainder of 563.
Put 7 as the next digit of the answer. 
Result so far: 317.0
Subtract 4515 from 5078 to get 563.
Include the next digit (4) from the dividend after 563, then repeat: 5634 / 645

Advancing to step 7:
645 goes into 5634 8 times with a remainder of 474.
Put 8 as the next digit of the answer. 
Result so far: 3178.0
If we take 5160 away from 5634, we end up with 474.
Append the next digit (0) from the dividend to 474 and continue with: 4740 / 645

On to step 8:
645 goes into 4740 7 times with a remainder of 225.
Write down 7 as next digit of the result. 
Result so far: 31787.0
Subtract 4515 from 4740 to get 225.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2250, and continue the process.

Going ahead to step 9:
2250 divided by 645 is 3 with a remainder of 315.
Write down 3 as next digit of the result. 
Result so far: 31787.3
If we subtract 1935 from 2250, we get 315.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3150, and continue the process.

Going ahead to step 10:
If we divide 3150 by 645, we get 4 and a remainder of 570.
Use 4 as the next digit of our solution. 
Result so far: 31787.34
The remainder is 570 after subtracting 2580 from 3150.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5700, and continue the process.

Moving on to step 11:
When dividing 5700 by 645, we get 8 with a remainder of 540.
The next digit of our result is 8. 
Result so far: 31787.348
Deduct 5160 from 5700 and we're left with 540.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5400, and continue the process.

Going ahead to step 12:
645 can be fit into 5400 8 times, resulting in a remainder of 240.
Put 8 as the next digit of the answer. 
Result so far: 31787.3488
Subtract 5160 from 5400 to get 240.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2400, and continue the process.

After the division, we end up with 31787.3488 and a remainder of 0.0024.