We look at the division of 521029 by 12 
Let's see how many times 12 fits into 521029.

Moving on to step 1:
When dividing 5 by 12, we get 0 with a remainder of 5.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we take 0 away from 5, we end up with 5.
Include the next digit (2) from the dividend after 5, then repeat: 52 / 12

Step 2:
If we divide 52 by 12, we get 4 and a remainder of 4.
Use 4 as the next digit of our solution. 
Result so far: 4.0
If we subtract 48 from 52, we get 4.
Grab the next digit (1) from the dividend, add it to 4, then carry on: 41 / 12

On to step 3:
When dividing 41 by 12, we get 3 with a remainder of 5.
Use 3 as the next digit of our solution. 
Result so far: 43.0
The remainder is 5 after subtracting 36 from 41.
Fetch the next digit (0) from the dividend, attach it to 5 and continue: 50 / 12

Let's proceed to step 4:
If we divide 50 by 12, we get 4 and a remainder of 2.
Record the quotient 4 as the next digit in the result. 
Result so far: 434.0
Subtract 48 from 50 to get 2.
Grab the next digit (2) from the dividend, add it to 2, then carry on: 22 / 12

Moving on to step 5:
22 divided by 12 is 1 with a remainder of 10.
Put 1 as the next digit of the answer. 
Result so far: 4341.0
The remainder is 10 after subtracting 12 from 22.
Grab the next digit (9) from the dividend, add it to 10, then carry on: 109 / 12

Let's proceed to step 6:
When dividing 109 by 12, we get 9 with a remainder of 1.
The number 9 becomes the next digit in our result. 
Result so far: 43419.0
If we subtract 108 from 109, we get 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Moving on to step 7:
12 can be fit into 10 0 times, resulting in a remainder of 10.
The next digit of our result is 0. 
Result so far: 43419.0
If we take 0 away from 10, we end up with 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Advancing to step 8:
12 goes into 100 8 times with a remainder of 4.
The number 8 becomes the next digit in our result. 
Result so far: 43419.08
The remainder is 4 after subtracting 96 from 100.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Step 9:
The number 12 fits into 40 3 times, leaving a remainder of 4.
The number 3 becomes the next digit in our result. 
Result so far: 43419.083
If we subtract 36 from 40, we get 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Let's proceed to step 10:
40 divided by 12 is 3 with a remainder of 4.
Write down 3 as next digit of the result. 
Result so far: 43419.0833
Subtract 36 from 40 to get 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 outcome is 43419.0833, with a leftover of 4e-05.