Let's divide 507421 by 42
The aim is to understand the frequency of 42 in 507421.

Step 1:
When dividing 5 by 42, we get 0 with a remainder of 5.
The next digit of our result is 0. 
Result so far: 0.0
Subtract 0 from 5 to get 5.
Grab the next digit (0) from the dividend, add it to 5, then carry on: 50 / 42

Moving on to step 2:
If we divide 50 by 42, we get 1 and a remainder of 8.
The number 1 becomes the next digit in our result. 
Result so far: 1.0
If we take 42 away from 50, we end up with 8.
Include the next digit (7) from the dividend after 8, then repeat: 87 / 42

Going ahead to step 3:
42 goes into 87 2 times with a remainder of 3.
Use 2 as the next digit of our solution. 
Result so far: 12.0
Subtracting 84 from 87 leaves us with 3.
Grab the next digit (4) from the dividend, add it to 3, then carry on: 34 / 42

On to step 4:
If we divide 34 by 42, we get 0 and a remainder of 34.
The number 0 becomes the next digit in our result. 
Result so far: 120.0
Deduct 0 from 34 and we're left with 34.
Include the next digit (2) from the dividend after 34, then repeat: 342 / 42

Advancing to step 5:
42 goes into 342 8 times with a remainder of 6.
The number 8 becomes the next digit in our result. 
Result so far: 1208.0
If we subtract 336 from 342, we get 6.
Grab the next digit (1) from the dividend, add it to 6, then carry on: 61 / 42

Going ahead to step 6:
When dividing 61 by 42, we get 1 with a remainder of 19.
Put 1 as the next digit of the answer. 
Result so far: 12081.0
If we subtract 42 from 61, we get 19.
Since there are no more digits in the dividend, we add a zero to the remainder making it 190, and continue the process.

On to step 7:
42 can be fit into 190 4 times, resulting in a remainder of 22.
Write down 4 as next digit of the result. 
Result so far: 12081.4
If we take 168 away from 190, we end up with 22.
Since there are no more digits in the dividend, we add a zero to the remainder making it 220, and continue the process.

Step 8:
If we divide 220 by 42, we get 5 and a remainder of 10.
Write down 5 as next digit of the result. 
Result so far: 12081.45
The remainder is 10 after subtracting 210 from 220.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Advancing to step 9:
42 can be fit into 100 2 times, resulting in a remainder of 16.
Write down 2 as next digit of the result. 
Result so far: 12081.452
Subtracting 84 from 100 leaves us with 16.
Since there are no more digits in the dividend, we add a zero to the remainder making it 160, and continue the process.

On to step 10:
42 can be fit into 160 3 times, resulting in a remainder of 34.
Record the quotient 3 as the next digit in the result. 
Result so far: 12081.4523
If we subtract 126 from 160, we get 34.
Since there are no more digits in the dividend, we add a zero to the remainder making it 340, and continue the process.

Let's proceed to step 11:
42 goes into 340 8 times with a remainder of 4.
Use 8 as the next digit of our solution. 
Result so far: 12081.45238
If we subtract 336 from 340, we get 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 12:
42 goes into 40 0 times with a remainder of 40.
The next digit of our result is 0. 
Result so far: 12081.45238
If we take 0 away from 40, we end up with 40.
Since there are no more digits in the dividend, we add a zero to the remainder making it 400, and continue the process.

Step 13:
42 can be fit into 400 9 times, resulting in a remainder of 22.
Write down 9 as next digit of the result. 
Result so far: 12081.4523809
Subtract 378 from 400 to get 22.
Since there are no more digits in the dividend, we add a zero to the remainder making it 220, and continue the process.

Advancing to step 14:
When dividing 220 by 42, we get 5 with a remainder of 10.
Put 5 as the next digit of the answer. 
Result so far: 12081.45238095
Subtracting 210 from 220 leaves us with 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

The final result is 12081.45238095 with a remainder of 1e-08.