We divide 53142146 by 12
Let's see how many times 12 fits into 53142146.

On to step 1:
When dividing 5 by 12, we get 0 with a remainder of 5.
The next digit of our result is 0. 
Result so far: 0.0
Subtract 0 from 5 to get 5.
Include the next digit (3) from the dividend after 5, then repeat: 53 / 12

Step 2:
If we divide 53 by 12, we get 4 and a remainder of 5.
Use 4 as the next digit of our solution. 
Result so far: 4.0
If we subtract 48 from 53, we get 5.
Bring next digit (1) of the dividend behind the 5 and repeat the process: 51 / 12

Advancing to step 3:
12 can be fit into 51 4 times, resulting in a remainder of 3.
The number 4 becomes the next digit in our result. 
Result so far: 44.0
If we subtract 48 from 51, we get 3.
Fetch the next digit (4) from the dividend, attach it to 3 and continue: 34 / 12

On to step 4:
When dividing 34 by 12, we get 2 with a remainder of 10.
The next digit of our result is 2. 
Result so far: 442.0
Subtract 24 from 34 to get 10.
Take the next digit (2) from the dividend and append it to 10, then repeat: 102 / 12

Going ahead to step 5:
If we divide 102 by 12, we get 8 and a remainder of 6.
The number 8 becomes the next digit in our result. 
Result so far: 4428.0
If we subtract 96 from 102, we get 6.
Take the next digit (1) from the dividend and append it to 6, then repeat: 61 / 12

Advancing to step 6:
If we divide 61 by 12, we get 5 and a remainder of 1.
Write down 5 as next digit of the result. 
Result so far: 44285.0
Subtracting 60 from 61 leaves us with 1.
Fetch the next digit (4) from the dividend, attach it to 1 and continue: 14 / 12

On to step 7:
If we divide 14 by 12, we get 1 and a remainder of 2.
Put 1 as the next digit of the answer. 
Result so far: 442851.0
Subtracting 12 from 14 leaves us with 2.
Fetch the next digit (6) from the dividend, attach it to 2 and continue: 26 / 12

Let's proceed to step 8:
The number 12 fits into 26 2 times, leaving a remainder of 2.
The next digit of our result is 2. 
Result so far: 4428512.0
If we take 24 away from 26, we end up with 2.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

Let's proceed to step 9:
If we divide 20 by 12, we get 1 and a remainder of 8.
Record the quotient 1 as the next digit in the result. 
Result so far: 4428512.1
Subtract 12 from 20 to get 8.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

Step 10:
When dividing 80 by 12, we get 6 with a remainder of 8.
The number 6 becomes the next digit in our result. 
Result so far: 4428512.16
If we subtract 72 from 80, we get 8.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

Let's proceed to step 11:
If we divide 80 by 12, we get 6 and a remainder of 8.
Put 6 as the next digit of the answer. 
Result so far: 4428512.166
Deduct 72 from 80 and we're left with 8.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

After the division, we end up with 4428512.166 and a remainder of 0.0008.