We look at the division of 353872 by 12 
We're looking to find how many times 12 goes into 353872.

Going ahead to step 1:
The number 12 fits into 3 0 times, leaving a remainder of 3.
The next digit of our result is 0. 
Result so far: 0.0
If we subtract 0 from 3, we get 3.
Fetch the next digit (5) from the dividend, attach it to 3 and continue: 35 / 12

On to step 2:
12 can be fit into 35 2 times, resulting in a remainder of 11.
The number 2 becomes the next digit in our result. 
Result so far: 2.0
Subtract 24 from 35 to get 11.
Append the next digit (3) from the dividend to 11 and continue with: 113 / 12

Going ahead to step 3:
When dividing 113 by 12, we get 9 with a remainder of 5.
The number 9 becomes the next digit in our result. 
Result so far: 29.0
Subtracting 108 from 113 leaves us with 5.
Append the next digit (8) from the dividend to 5 and continue with: 58 / 12

Going ahead to step 4:
12 goes into 58 4 times with a remainder of 10.
The next digit of our result is 4. 
Result so far: 294.0
If we subtract 48 from 58, we get 10.
Fetch the next digit (7) from the dividend, attach it to 10 and continue: 107 / 12

Going ahead to step 5:
12 can be fit into 107 8 times, resulting in a remainder of 11.
Record the quotient 8 as the next digit in the result. 
Result so far: 2948.0
Subtracting 96 from 107 leaves us with 11.
Bring next digit (2) of the dividend behind the 11 and repeat the process: 112 / 12

Step 6:
If we divide 112 by 12, we get 9 and a remainder of 4.
The number 9 becomes the next digit in our result. 
Result so far: 29489.0
Deduct 108 from 112 and we're left with 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Step 7:
If we divide 40 by 12, we get 3 and a remainder of 4.
The number 3 becomes the next digit in our result. 
Result so far: 29489.3
Subtracting 36 from 40 leaves us with 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Moving on to step 8:
12 goes into 40 3 times with a remainder of 4.
Write down 3 as next digit of the result. 
Result so far: 29489.33
If we take 36 away from 40, we end up with 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

The final result is 29489.33 with a remainder of 0.004.