309861 ÷ 12 
We're looking to find how many times 12 goes into 309861.

Advancing to step 1:
12 can be fit into 3 0 times, resulting in a remainder of 3.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Deduct 0 from 3 and we're left with 3.
Fetch the next digit (0) from the dividend, attach it to 3 and continue: 30 / 12

On to step 2:
If we divide 30 by 12, we get 2 and a remainder of 6.
The number 2 becomes the next digit in our result. 
Result so far: 2.0
Subtracting 24 from 30 leaves us with 6.
Take the next digit (9) from the dividend and append it to 6, then repeat: 69 / 12

On to step 3:
69 divided by 12 is 5 with a remainder of 9.
The number 5 becomes the next digit in our result. 
Result so far: 25.0
If we take 60 away from 69, we end up with 9.
Bring next digit (8) of the dividend behind the 9 and repeat the process: 98 / 12

Let's proceed to step 4:
12 can be fit into 98 8 times, resulting in a remainder of 2.
The next digit of our result is 8. 
Result so far: 258.0
If we take 96 away from 98, we end up with 2.
Include the next digit (6) from the dividend after 2, then repeat: 26 / 12

Advancing to step 5:
When dividing 26 by 12, we get 2 with a remainder of 2.
The number 2 becomes the next digit in our result. 
Result so far: 2582.0
Subtract 24 from 26 to get 2.
Take the next digit (1) from the dividend and append it to 2, then repeat: 21 / 12

Step 6:
The number 12 fits into 21 1 times, leaving a remainder of 9.
The next digit of our result is 1. 
Result so far: 25821.0
Deduct 12 from 21 and we're left with 9.
Since there are no more digits in the dividend, we add a zero to the remainder making it 90, and continue the process.

Step 7:
90 divided by 12 is 7 with a remainder of 6.
The number 7 becomes the next digit in our result. 
Result so far: 25821.7
Subtracting 84 from 90 leaves us with 6.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

Going ahead to step 8:
12 goes into 60 5 times with a remainder of 0.
The number 5 becomes the next digit in our result. 
Result so far: 25821.75
Deduct 60 from 60 and we're left with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

On to step 9:
12 can be fit into 0 0 times, resulting in a remainder of 0.
The next digit of our result is 0. 
Result so far: 25821.75
Subtracting 0 from 0 leaves us with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Step 10:
When dividing 0 by 12, we get 0 with a remainder of 0.
Record the quotient 0 as the next digit in the result. 
Result so far: 25821.75
If we take 0 away from 0, we end up with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

The quotient of the division is 25821.75, and the remainder is 0.0.