We look at the division of 351435 by 87 
The aim is to understand the frequency of 87 in 351435.

On to step 1:
87 goes into 3 0 times with a remainder of 3.
The next digit of our result is 0. 
Result so far: 0.0
Subtract 0 from 3 to get 3.
Bring next digit (5) of the dividend behind the 3 and repeat the process: 35 / 87

Advancing to step 2:
87 goes into 35 0 times with a remainder of 35.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtracting 0 from 35 leaves us with 35.
Take the next digit (1) from the dividend and append it to 35, then repeat: 351 / 87

Step 3:
If we divide 351 by 87, we get 4 and a remainder of 3.
Write down 4 as next digit of the result. 
Result so far: 4.0
If we take 348 away from 351, we end up with 3.
Include the next digit (4) from the dividend after 3, then repeat: 34 / 87

Let's proceed to step 4:
34 divided by 87 is 0 with a remainder of 34.
Put 0 as the next digit of the answer. 
Result so far: 40.0
Subtracting 0 from 34 leaves us with 34.
Include the next digit (3) from the dividend after 34, then repeat: 343 / 87

Advancing to step 5:
87 goes into 343 3 times with a remainder of 82.
Record the quotient 3 as the next digit in the result. 
Result so far: 403.0
Subtracting 261 from 343 leaves us with 82.
Append the next digit (5) from the dividend to 82 and continue with: 825 / 87

Moving on to step 6:
87 goes into 825 9 times with a remainder of 42.
Put 9 as the next digit of the answer. 
Result so far: 4039.0
The remainder is 42 after subtracting 783 from 825.
Since there are no more digits in the dividend, we add a zero to the remainder making it 420, and continue the process.

Step 7:
87 goes into 420 4 times with a remainder of 72.
Put 4 as the next digit of the answer. 
Result so far: 4039.4
Subtracting 348 from 420 leaves us with 72.
Since there are no more digits in the dividend, we add a zero to the remainder making it 720, and continue the process.

Advancing to step 8:
When dividing 720 by 87, we get 8 with a remainder of 24.
Write down 8 as next digit of the result. 
Result so far: 4039.48
The remainder is 24 after subtracting 696 from 720.
Since there are no more digits in the dividend, we add a zero to the remainder making it 240, and continue the process.

Going ahead to step 9:
The number 87 fits into 240 2 times, leaving a remainder of 66.
The next digit of our result is 2. 
Result so far: 4039.482
If we subtract 174 from 240, we get 66.
Since there are no more digits in the dividend, we add a zero to the remainder making it 660, and continue the process.

Moving on to step 10:
660 divided by 87 is 7 with a remainder of 51.
The number 7 becomes the next digit in our result. 
Result so far: 4039.4827
Subtracting 609 from 660 leaves us with 51.
Since there are no more digits in the dividend, we add a zero to the remainder making it 510, and continue the process.

Moving on to step 11:
87 goes into 510 5 times with a remainder of 75.
Use 5 as the next digit of our solution. 
Result so far: 4039.48275
The remainder is 75 after subtracting 435 from 510.
Since there are no more digits in the dividend, we add a zero to the remainder making it 750, and continue the process.

Moving on to step 12:
The number 87 fits into 750 8 times, leaving a remainder of 54.
Record the quotient 8 as the next digit in the result. 
Result so far: 4039.482758
Subtracting 696 from 750 leaves us with 54.
Since there are no more digits in the dividend, we add a zero to the remainder making it 540, and continue the process.

Advancing to step 13:
87 can be fit into 540 6 times, resulting in a remainder of 18.
Record the quotient 6 as the next digit in the result. 
Result so far: 4039.4827586
Subtract 522 from 540 to get 18.
Since there are no more digits in the dividend, we add a zero to the remainder making it 180, and continue the process.

Moving on to step 14:
87 can be fit into 180 2 times, resulting in a remainder of 6.
The next digit of our result is 2. 
Result so far: 4039.48275862
Deduct 174 from 180 and we're left with 6.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

The final result is 4039.48275862 with a remainder of 6e-09.