Let's divide 421241 by 1
The aim is to understand the frequency of 1 in 421241.

Moving on to step 1:
4 divided by 1 is 4 with a remainder of 0.
The next digit of our result is 4. 
Result so far: 4.0
The remainder is 0 after subtracting 4 from 4.
Grab the next digit (2) from the dividend, add it to 0, then carry on: 2 / 1

On to step 2:
1 goes into 2 2 times with a remainder of 0.
Put 2 as the next digit of the answer. 
Result so far: 42.0
Subtracting 2 from 2 leaves us with 0.
Append the next digit (1) from the dividend to 0 and continue with: 1 / 1

Step 3:
The number 1 fits into 1 1 times, leaving a remainder of 0.
The next digit of our result is 1. 
Result so far: 421.0
Subtract 1 from 1 to get 0.
Fetch the next digit (2) from the dividend, attach it to 0 and continue: 2 / 1

Moving on to step 4:
2 divided by 1 is 2 with a remainder of 0.
Record the quotient 2 as the next digit in the result. 
Result so far: 4212.0
Subtracting 2 from 2 leaves us with 0.
Include the next digit (4) from the dividend after 0, then repeat: 4 / 1

Let's proceed to step 5:
1 goes into 4 4 times with a remainder of 0.
Record the quotient 4 as the next digit in the result. 
Result so far: 42124.0
Deduct 4 from 4 and we're left with 0.
Fetch the next digit (1) from the dividend, attach it to 0 and continue: 1 / 1

Moving on to step 6:
The number 1 fits into 1 1 times, leaving a remainder of 0.
The next digit of our result is 1. 
Result so far: 421241.0
The remainder is 0 after subtracting 1 from 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Advancing to step 7:
When dividing 0 by 1, we get 0 with a remainder of 0.
Write down 0 as next digit of the result. 
Result so far: 421241.0
The remainder is 0 after subtracting 0 from 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

On to step 8:
1 goes into 0 0 times with a remainder of 0.
Write down 0 as next digit of the result. 
Result so far: 421241.0
Subtract 0 from 0 to get 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

The final outcome is 421241.0, with a leftover of 0.0.