12303121 divided by 810 
We want to figure out the number of times 12303121 can be divided by 810.

Moving on to step 1:
810 can be fit into 1 0 times, resulting in a remainder of 1.
The next digit of our result is 0. 
Result so far: 0.0
The remainder is 1 after subtracting 0 from 1.
Include the next digit (2) from the dividend after 1, then repeat: 12 / 810

Advancing to step 2:
810 can be fit into 12 0 times, resulting in a remainder of 12.
Write down 0 as next digit of the result. 
Result so far: 0.0
The remainder is 12 after subtracting 0 from 12.
Take the next digit (3) from the dividend and append it to 12, then repeat: 123 / 810

Moving on to step 3:
123 divided by 810 is 0 with a remainder of 123.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we subtract 0 from 123, we get 123.
Append the next digit (0) from the dividend to 123 and continue with: 1230 / 810

Let's proceed to step 4:
If we divide 1230 by 810, we get 1 and a remainder of 420.
The next digit of our result is 1. 
Result so far: 1.0
Subtracting 810 from 1230 leaves us with 420.
Append the next digit (3) from the dividend to 420 and continue with: 4203 / 810

Moving on to step 5:
If we divide 4203 by 810, we get 5 and a remainder of 153.
Use 5 as the next digit of our solution. 
Result so far: 15.0
Deduct 4050 from 4203 and we're left with 153.
Grab the next digit (1) from the dividend, add it to 153, then carry on: 1531 / 810

Advancing to step 6:
810 goes into 1531 1 times with a remainder of 721.
The number 1 becomes the next digit in our result. 
Result so far: 151.0
If we subtract 810 from 1531, we get 721.
Take the next digit (2) from the dividend and append it to 721, then repeat: 7212 / 810

Advancing to step 7:
The number 810 fits into 7212 8 times, leaving a remainder of 732.
Use 8 as the next digit of our solution. 
Result so far: 1518.0
If we subtract 6480 from 7212, we get 732.
Append the next digit (1) from the dividend to 732 and continue with: 7321 / 810

Going ahead to step 8:
When dividing 7321 by 810, we get 9 with a remainder of 31.
The number 9 becomes the next digit in our result. 
Result so far: 15189.0
If we subtract 7290 from 7321, we get 31.
Since there are no more digits in the dividend, we add a zero to the remainder making it 310, and continue the process.

Step 9:
The number 810 fits into 310 0 times, leaving a remainder of 310.
The next digit of our result is 0. 
Result so far: 15189.0
If we take 0 away from 310, we end up with 310.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3100, and continue the process.

Step 10:
810 can be fit into 3100 3 times, resulting in a remainder of 670.
Put 3 as the next digit of the answer. 
Result so far: 15189.03
Deduct 2430 from 3100 and we're left with 670.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6700, and continue the process.

Advancing to step 11:
When dividing 6700 by 810, we get 8 with a remainder of 220.
The next digit of our result is 8. 
Result so far: 15189.038
If we take 6480 away from 6700, we end up with 220.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2200, and continue the process.

Step 12:
If we divide 2200 by 810, we get 2 and a remainder of 580.
The number 2 becomes the next digit in our result. 
Result so far: 15189.0382
If we subtract 1620 from 2200, we get 580.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5800, and continue the process.

Step 13:
When dividing 5800 by 810, we get 7 with a remainder of 130.
Put 7 as the next digit of the answer. 
Result so far: 15189.03827
If we take 5670 away from 5800, we end up with 130.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1300, and continue the process.

Going ahead to step 14:
1300 divided by 810 is 1 with a remainder of 490.
Record the quotient 1 as the next digit in the result. 
Result so far: 15189.038271
If we take 810 away from 1300, we end up with 490.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4900, and continue the process.

Step 15:
When dividing 4900 by 810, we get 6 with a remainder of 40.
The number 6 becomes the next digit in our result. 
Result so far: 15189.0382716
If we take 4860 away from 4900, we end up with 40.
Since there are no more digits in the dividend, we add a zero to the remainder making it 400, and continue the process.

Step 16:
810 goes into 400 0 times with a remainder of 400.
Write down 0 as next digit of the result. 
Result so far: 15189.0382716
Subtract 0 from 400 to get 400.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4000, and continue the process.

After the division, we end up with 15189.0382716 and a remainder of 4e-07.