90431 ÷ 42 
We want to figure out the number of times 90431 can be divided by 42.

Step 1:
42 can be fit into 9 0 times, resulting in a remainder of 9.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Deduct 0 from 9 and we're left with 9.
Take the next digit (0) from the dividend and append it to 9, then repeat: 90 / 42

Advancing to step 2:
90 divided by 42 is 2 with a remainder of 6.
Put 2 as the next digit of the answer. 
Result so far: 2.0
Deduct 84 from 90 and we're left with 6.
Fetch the next digit (4) from the dividend, attach it to 6 and continue: 64 / 42

Let's proceed to step 3:
The number 42 fits into 64 1 times, leaving a remainder of 22.
Put 1 as the next digit of the answer. 
Result so far: 21.0
Deduct 42 from 64 and we're left with 22.
Grab the next digit (3) from the dividend, add it to 22, then carry on: 223 / 42

Going ahead to step 4:
223 divided by 42 is 5 with a remainder of 13.
The number 5 becomes the next digit in our result. 
Result so far: 215.0
Deduct 210 from 223 and we're left with 13.
Take the next digit (1) from the dividend and append it to 13, then repeat: 131 / 42

On to step 5:
42 can be fit into 131 3 times, resulting in a remainder of 5.
Write down 3 as next digit of the result. 
Result so far: 2153.0
Deduct 126 from 131 and we're left with 5.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

Moving on to step 6:
If we divide 50 by 42, we get 1 and a remainder of 8.
Use 1 as the next digit of our solution. 
Result so far: 2153.1
The remainder is 8 after subtracting 42 from 50.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

Step 7:
The number 42 fits into 80 1 times, leaving a remainder of 38.
Use 1 as the next digit of our solution. 
Result so far: 2153.11
Deduct 42 from 80 and we're left with 38.
Since there are no more digits in the dividend, we add a zero to the remainder making it 380, and continue the process.

After the division, we end up with 2153.11 and a remainder of 0.038.