86781793 ÷ 42 
The aim is to understand the frequency of 42 in 86781793.

Advancing to step 1:
The number 42 fits into 8 0 times, leaving a remainder of 8.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtracting 0 from 8 leaves us with 8.
Fetch the next digit (6) from the dividend, attach it to 8 and continue: 86 / 42

Going ahead to step 2:
When dividing 86 by 42, we get 2 with a remainder of 2.
Record the quotient 2 as the next digit in the result. 
Result so far: 2.0
If we subtract 84 from 86, we get 2.
Include the next digit (7) from the dividend after 2, then repeat: 27 / 42

Let's proceed to step 3:
The number 42 fits into 27 0 times, leaving a remainder of 27.
The next digit of our result is 0. 
Result so far: 20.0
Subtract 0 from 27 to get 27.
Bring next digit (8) of the dividend behind the 27 and repeat the process: 278 / 42

Step 4:
278 divided by 42 is 6 with a remainder of 26.
Record the quotient 6 as the next digit in the result. 
Result so far: 206.0
The remainder is 26 after subtracting 252 from 278.
Bring next digit (1) of the dividend behind the 26 and repeat the process: 261 / 42

On to step 5:
If we divide 261 by 42, we get 6 and a remainder of 9.
Use 6 as the next digit of our solution. 
Result so far: 2066.0
Subtracting 252 from 261 leaves us with 9.
Take the next digit (7) from the dividend and append it to 9, then repeat: 97 / 42

Let's proceed to step 6:
97 divided by 42 is 2 with a remainder of 13.
Record the quotient 2 as the next digit in the result. 
Result so far: 20662.0
Deduct 84 from 97 and we're left with 13.
Grab the next digit (9) from the dividend, add it to 13, then carry on: 139 / 42

Going ahead to step 7:
42 can be fit into 139 3 times, resulting in a remainder of 13.
Record the quotient 3 as the next digit in the result. 
Result so far: 206623.0
The remainder is 13 after subtracting 126 from 139.
Bring next digit (3) of the dividend behind the 13 and repeat the process: 133 / 42

Moving on to step 8:
The number 42 fits into 133 3 times, leaving a remainder of 7.
Write down 3 as next digit of the result. 
Result so far: 2066233.0
If we take 126 away from 133, we end up with 7.
Since there are no more digits in the dividend, we add a zero to the remainder making it 70, and continue the process.

Moving on to step 9:
The number 42 fits into 70 1 times, leaving a remainder of 28.
Record the quotient 1 as the next digit in the result. 
Result so far: 2066233.1
If we take 42 away from 70, we end up with 28.
Since there are no more digits in the dividend, we add a zero to the remainder making it 280, and continue the process.

On to step 10:
42 can be fit into 280 6 times, resulting in a remainder of 28.
The number 6 becomes the next digit in our result. 
Result so far: 2066233.16
If we take 252 away from 280, we end up with 28.
Since there are no more digits in the dividend, we add a zero to the remainder making it 280, and continue the process.

Let's proceed to step 11:
42 can be fit into 280 6 times, resulting in a remainder of 28.
Put 6 as the next digit of the answer. 
Result so far: 2066233.166
Deduct 252 from 280 and we're left with 28.
Since there are no more digits in the dividend, we add a zero to the remainder making it 280, and continue the process.

The final outcome is 2066233.166, with a leftover of 0.0028.