We look at the division of 12817539 by 858 
The aim is to understand the frequency of 858 in 12817539.

Step 1:
The number 858 fits into 1 0 times, leaving a remainder of 1.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
If we subtract 0 from 1, we get 1.
Bring next digit (2) of the dividend behind the 1 and repeat the process: 12 / 858

Step 2:
12 divided by 858 is 0 with a remainder of 12.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
The remainder is 12 after subtracting 0 from 12.
Append the next digit (8) from the dividend to 12 and continue with: 128 / 858

Going ahead to step 3:
128 divided by 858 is 0 with a remainder of 128.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
If we subtract 0 from 128, we get 128.
Include the next digit (1) from the dividend after 128, then repeat: 1281 / 858

Advancing to step 4:
858 goes into 1281 1 times with a remainder of 423.
The next digit of our result is 1. 
Result so far: 1.0
Subtracting 858 from 1281 leaves us with 423.
Append the next digit (7) from the dividend to 423 and continue with: 4237 / 858

Moving on to step 5:
The number 858 fits into 4237 4 times, leaving a remainder of 805.
Put 4 as the next digit of the answer. 
Result so far: 14.0
The remainder is 805 after subtracting 3432 from 4237.
Bring next digit (5) of the dividend behind the 805 and repeat the process: 8055 / 858

Let's proceed to step 6:
When dividing 8055 by 858, we get 9 with a remainder of 333.
The number 9 becomes the next digit in our result. 
Result so far: 149.0
The remainder is 333 after subtracting 7722 from 8055.
Grab the next digit (3) from the dividend, add it to 333, then carry on: 3333 / 858

Going ahead to step 7:
858 goes into 3333 3 times with a remainder of 759.
The next digit of our result is 3. 
Result so far: 1493.0
Deduct 2574 from 3333 and we're left with 759.
Take the next digit (9) from the dividend and append it to 759, then repeat: 7599 / 858

Going ahead to step 8:
858 can be fit into 7599 8 times, resulting in a remainder of 735.
Use 8 as the next digit of our solution. 
Result so far: 14938.0
If we take 6864 away from 7599, we end up with 735.
Since there are no more digits in the dividend, we add a zero to the remainder making it 7350, and continue the process.

Let's proceed to step 9:
When dividing 7350 by 858, we get 8 with a remainder of 486.
Use 8 as the next digit of our solution. 
Result so far: 14938.8
The remainder is 486 after subtracting 6864 from 7350.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4860, and continue the process.

Going ahead to step 10:
858 goes into 4860 5 times with a remainder of 570.
Write down 5 as next digit of the result. 
Result so far: 14938.85
If we subtract 4290 from 4860, we get 570.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5700, and continue the process.

Let's proceed to step 11:
The number 858 fits into 5700 6 times, leaving a remainder of 552.
The number 6 becomes the next digit in our result. 
Result so far: 14938.856
Subtracting 5148 from 5700 leaves us with 552.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5520, and continue the process.

Advancing to step 12:
If we divide 5520 by 858, we get 6 and a remainder of 372.
Record the quotient 6 as the next digit in the result. 
Result so far: 14938.8566
The remainder is 372 after subtracting 5148 from 5520.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3720, and continue the process.

The quotient of the division is 14938.8566, and the remainder is 0.00372.