We look at the division of 286690 by 12 
The aim is to understand the frequency of 12 in 286690.

On to step 1:
The number 12 fits into 2 0 times, leaving a remainder of 2.
The next digit of our result is 0. 
Result so far: 0.0
Deduct 0 from 2 and we're left with 2.
Include the next digit (8) from the dividend after 2, then repeat: 28 / 12

Step 2:
When dividing 28 by 12, we get 2 with a remainder of 4.
Use 2 as the next digit of our solution. 
Result so far: 2.0
If we take 24 away from 28, we end up with 4.
Fetch the next digit (6) from the dividend, attach it to 4 and continue: 46 / 12

Advancing to step 3:
When dividing 46 by 12, we get 3 with a remainder of 10.
Use 3 as the next digit of our solution. 
Result so far: 23.0
Subtract 36 from 46 to get 10.
Grab the next digit (6) from the dividend, add it to 10, then carry on: 106 / 12

Let's proceed to step 4:
106 divided by 12 is 8 with a remainder of 10.
Put 8 as the next digit of the answer. 
Result so far: 238.0
Subtracting 96 from 106 leaves us with 10.
Append the next digit (9) from the dividend to 10 and continue with: 109 / 12

On to step 5:
12 goes into 109 9 times with a remainder of 1.
The number 9 becomes the next digit in our result. 
Result so far: 2389.0
Subtracting 108 from 109 leaves us with 1.
Grab the next digit (0) from the dividend, add it to 1, then carry on: 10 / 12

Going ahead to step 6:
The number 12 fits into 10 0 times, leaving a remainder of 10.
The next digit of our result is 0. 
Result so far: 23890.0
Subtract 0 from 10 to get 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 7:
When dividing 100 by 12, we get 8 with a remainder of 4.
Write down 8 as next digit of the result. 
Result so far: 23890.8
If we subtract 96 from 100, 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.

Going ahead to step 8:
When dividing 40 by 12, we get 3 with a remainder of 4.
The number 3 becomes the next digit in our result. 
Result so far: 23890.83
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.

Going ahead to step 9:
If we divide 40 by 12, we get 3 and a remainder of 4.
Write down 3 as next digit of the result. 
Result so far: 23890.833
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.

The final result is 23890.833 with a remainder of 0.0004.