102820 ÷ 12 
The aim is to understand the frequency of 12 in 102820.

Step 1:
If we divide 1 by 12, we get 0 and a remainder of 1.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtract 0 from 1 to get 1.
Take the next digit (0) from the dividend and append it to 1, then repeat: 10 / 12

Advancing to step 2:
When dividing 10 by 12, we get 0 with a remainder of 10.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
The remainder is 10 after subtracting 0 from 10.
Take the next digit (2) from the dividend and append it to 10, then repeat: 102 / 12

Moving on to step 3:
12 can be fit into 102 8 times, resulting in a remainder of 6.
Write down 8 as next digit of the result. 
Result so far: 8.0
Deduct 96 from 102 and we're left with 6.
Fetch the next digit (8) from the dividend, attach it to 6 and continue: 68 / 12

Moving on to step 4:
12 can be fit into 68 5 times, resulting in a remainder of 8.
Put 5 as the next digit of the answer. 
Result so far: 85.0
Subtract 60 from 68 to get 8.
Take the next digit (2) from the dividend and append it to 8, then repeat: 82 / 12

On to step 5:
12 goes into 82 6 times with a remainder of 10.
The number 6 becomes the next digit in our result. 
Result so far: 856.0
The remainder is 10 after subtracting 72 from 82.
Fetch the next digit (0) from the dividend, attach it to 10 and continue: 100 / 12

Moving on to step 6:
12 goes into 100 8 times with a remainder of 4.
Put 8 as the next digit of the answer. 
Result so far: 8568.0
If we take 96 away from 100, 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.

On to step 7:
When dividing 40 by 12, we get 3 with a remainder of 4.
Use 3 as the next digit of our solution. 
Result so far: 8568.3
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.

On to step 8:
If we divide 40 by 12, we get 3 and a remainder of 4.
Put 3 as the next digit of the answer. 
Result so far: 8568.33
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.

Our division results in 8568.33 with a remaining 0.004.