We look at the division of 350590 by 87 
The aim is to understand the frequency of 87 in 350590.

Let's proceed to step 1:
The number 87 fits into 3 0 times, leaving a remainder of 3.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Subtracting 0 from 3 leaves us with 3.
Include the next digit (5) from the dividend after 3, then repeat: 35 / 87

Moving on to step 2:
87 goes into 35 0 times with a remainder of 35.
Write down 0 as next digit of the result. 
Result so far: 0.0
Deduct 0 from 35 and we're left with 35.
Include the next digit (0) from the dividend after 35, then repeat: 350 / 87

Let's proceed to step 3:
When dividing 350 by 87, we get 4 with a remainder of 2.
Record the quotient 4 as the next digit in the result. 
Result so far: 4.0
Subtracting 348 from 350 leaves us with 2.
Grab the next digit (5) from the dividend, add it to 2, then carry on: 25 / 87

On to step 4:
87 can be fit into 25 0 times, resulting in a remainder of 25.
Write down 0 as next digit of the result. 
Result so far: 40.0
If we subtract 0 from 25, we get 25.
Bring next digit (9) of the dividend behind the 25 and repeat the process: 259 / 87

Advancing to step 5:
87 goes into 259 2 times with a remainder of 85.
The number 2 becomes the next digit in our result. 
Result so far: 402.0
Deduct 174 from 259 and we're left with 85.
Include the next digit (0) from the dividend after 85, then repeat: 850 / 87

On to step 6:
850 divided by 87 is 9 with a remainder of 67.
The next digit of our result is 9. 
Result so far: 4029.0
If we subtract 783 from 850, we get 67.
Since there are no more digits in the dividend, we add a zero to the remainder making it 670, and continue the process.

Advancing to step 7:
If we divide 670 by 87, we get 7 and a remainder of 61.
The number 7 becomes the next digit in our result. 
Result so far: 4029.7
If we subtract 609 from 670, we get 61.
Since there are no more digits in the dividend, we add a zero to the remainder making it 610, and continue the process.

Advancing to step 8:
When dividing 610 by 87, we get 7 with a remainder of 1.
The next digit of our result is 7. 
Result so far: 4029.77
Subtracting 609 from 610 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.

The final outcome is 4029.77, with a leftover of 0.001.