We're dividing 515881 by 12 
The aim is to understand the frequency of 12 in 515881.

Moving on to step 1:
12 can be fit into 5 0 times, resulting in a remainder of 5.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Deduct 0 from 5 and we're left with 5.
Grab the next digit (1) from the dividend, add it to 5, then carry on: 51 / 12

Step 2:
12 can be fit into 51 4 times, resulting in a remainder of 3.
The next digit of our result is 4. 
Result so far: 4.0
If we take 48 away from 51, we end up with 3.
Grab the next digit (5) from the dividend, add it to 3, then carry on: 35 / 12

Moving on to step 3:
35 divided by 12 is 2 with a remainder of 11.
Put 2 as the next digit of the answer. 
Result so far: 42.0
If we take 24 away from 35, we end up with 11.
Include the next digit (8) from the dividend after 11, then repeat: 118 / 12

Advancing to step 4:
When dividing 118 by 12, we get 9 with a remainder of 10.
Put 9 as the next digit of the answer. 
Result so far: 429.0
The remainder is 10 after subtracting 108 from 118.
Append the next digit (8) from the dividend to 10 and continue with: 108 / 12

On to step 5:
108 divided by 12 is 9 with a remainder of 0.
Record the quotient 9 as the next digit in the result. 
Result so far: 4299.0
Deduct 108 from 108 and we're left with 0.
Include the next digit (1) from the dividend after 0, then repeat: 1 / 12

Let's proceed to step 6:
1 divided by 12 is 0 with a remainder of 1.
Record the quotient 0 as the next digit in the result. 
Result so far: 42990.0
Subtracting 0 from 1 leaves us with 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

On to step 7:
12 goes into 10 0 times with a remainder of 10.
Record the quotient 0 as the next digit in the result. 
Result so far: 42990.0
Deduct 0 from 10 and we're left 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.

On to step 8:
When dividing 100 by 12, we get 8 with a remainder of 4.
Use 8 as the next digit of our solution. 
Result so far: 42990.08
Subtract 96 from 100 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.

Advancing to step 9:
The number 12 fits into 40 3 times, leaving a remainder of 4.
Put 3 as the next digit of the answer. 
Result so far: 42990.083
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.

Step 10:
40 divided by 12 is 3 with a remainder of 4.
The number 3 becomes the next digit in our result. 
Result so far: 42990.0833
The remainder is 4 after subtracting 36 from 40.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

After the division, we end up with 42990.0833 and a remainder of 4e-05.