We look at the division of 21090840 by 145 
Our goal is to divide 21090840 by 145.

Moving on to step 1:
When dividing 2 by 145, we get 0 with a remainder of 2.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtract 0 from 2 to get 2.
Take the next digit (1) from the dividend and append it to 2, then repeat: 21 / 145

Advancing to step 2:
The number 145 fits into 21 0 times, leaving a remainder of 21.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we take 0 away from 21, we end up with 21.
Bring next digit (0) of the dividend behind the 21 and repeat the process: 210 / 145

On to step 3:
210 divided by 145 is 1 with a remainder of 65.
Record the quotient 1 as the next digit in the result. 
Result so far: 1.0
Deduct 145 from 210 and we're left with 65.
Append the next digit (9) from the dividend to 65 and continue with: 659 / 145

Step 4:
145 goes into 659 4 times with a remainder of 79.
Write down 4 as next digit of the result. 
Result so far: 14.0
If we subtract 580 from 659, we get 79.
Take the next digit (0) from the dividend and append it to 79, then repeat: 790 / 145

Advancing to step 5:
790 divided by 145 is 5 with a remainder of 65.
The number 5 becomes the next digit in our result. 
Result so far: 145.0
Deduct 725 from 790 and we're left with 65.
Grab the next digit (8) from the dividend, add it to 65, then carry on: 658 / 145

Going ahead to step 6:
The number 145 fits into 658 4 times, leaving a remainder of 78.
The number 4 becomes the next digit in our result. 
Result so far: 1454.0
If we subtract 580 from 658, we get 78.
Append the next digit (4) from the dividend to 78 and continue with: 784 / 145

Advancing to step 7:
The number 145 fits into 784 5 times, leaving a remainder of 59.
Record the quotient 5 as the next digit in the result. 
Result so far: 14545.0
If we take 725 away from 784, we end up with 59.
Bring next digit (0) of the dividend behind the 59 and repeat the process: 590 / 145

Moving on to step 8:
590 divided by 145 is 4 with a remainder of 10.
The next digit of our result is 4. 
Result so far: 145454.0
If we subtract 580 from 590, we get 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Moving on to step 9:
145 can be fit into 100 0 times, resulting in a remainder of 100.
The number 0 becomes the next digit in our result. 
Result so far: 145454.0
The remainder is 100 after subtracting 0 from 100.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1000, and continue the process.

Going ahead to step 10:
145 can be fit into 1000 6 times, resulting in a remainder of 130.
The number 6 becomes the next digit in our result. 
Result so far: 145454.06
The remainder is 130 after subtracting 870 from 1000.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1300, and continue the process.

Advancing to step 11:
If we divide 1300 by 145, we get 8 and a remainder of 140.
The number 8 becomes the next digit in our result. 
Result so far: 145454.068
If we take 1160 away from 1300, we end up 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.

On to step 12:
When dividing 1400 by 145, we get 9 with a remainder of 95.
The next digit of our result is 9. 
Result so far: 145454.0689
The remainder is 95 after subtracting 1305 from 1400.
Since there are no more digits in the dividend, we add a zero to the remainder making it 950, and continue the process.

Let's proceed to step 13:
145 can be fit into 950 6 times, resulting in a remainder of 80.
The number 6 becomes the next digit in our result. 
Result so far: 145454.06896
Subtracting 870 from 950 leaves us with 80.
Since there are no more digits in the dividend, we add a zero to the remainder making it 800, and continue the process.

Moving on to step 14:
800 divided by 145 is 5 with a remainder of 75.
The number 5 becomes the next digit in our result. 
Result so far: 145454.068965
Subtract 725 from 800 to get 75.
Since there are no more digits in the dividend, we add a zero to the remainder making it 750, and continue the process.

Advancing to step 15:
750 divided by 145 is 5 with a remainder of 25.
The number 5 becomes the next digit in our result. 
Result so far: 145454.0689655
If we subtract 725 from 750, we get 25.
Since there are no more digits in the dividend, we add a zero to the remainder making it 250, and continue the process.

Our division results in 145454.0689655 with a remaining 2.5e-07.