642509 divided by 42 
We want to figure out the number of times 642509 can be divided by 42.

On to step 1:
42 goes into 6 0 times with a remainder of 6.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtracting 0 from 6 leaves us with 6.
Grab the next digit (4) from the dividend, add it to 6, then carry on: 64 / 42

Let's proceed to step 2:
When dividing 64 by 42, we get 1 with a remainder of 22.
Write down 1 as next digit of the result. 
Result so far: 1.0
If we take 42 away from 64, we end up with 22.
Include the next digit (2) from the dividend after 22, then repeat: 222 / 42

Step 3:
42 can be fit into 222 5 times, resulting in a remainder of 12.
The number 5 becomes the next digit in our result. 
Result so far: 15.0
If we take 210 away from 222, we end up with 12.
Append the next digit (5) from the dividend to 12 and continue with: 125 / 42

Moving on to step 4:
125 divided by 42 is 2 with a remainder of 41.
Use 2 as the next digit of our solution. 
Result so far: 152.0
Subtracting 84 from 125 leaves us with 41.
Bring next digit (0) of the dividend behind the 41 and repeat the process: 410 / 42

Advancing to step 5:
The number 42 fits into 410 9 times, leaving a remainder of 32.
Use 9 as the next digit of our solution. 
Result so far: 1529.0
If we subtract 378 from 410, we get 32.
Grab the next digit (9) from the dividend, add it to 32, then carry on: 329 / 42

Step 6:
The number 42 fits into 329 7 times, leaving a remainder of 35.
Use 7 as the next digit of our solution. 
Result so far: 15297.0
The remainder is 35 after subtracting 294 from 329.
Since there are no more digits in the dividend, we add a zero to the remainder making it 350, and continue the process.

On to step 7:
If we divide 350 by 42, we get 8 and a remainder of 14.
The number 8 becomes the next digit in our result. 
Result so far: 15297.8
Subtract 336 from 350 to get 14.
Since there are no more digits in the dividend, we add a zero to the remainder making it 140, and continue the process.

Going ahead to step 8:
If we divide 140 by 42, we get 3 and a remainder of 14.
The next digit of our result is 3. 
Result so far: 15297.83
The remainder is 14 after subtracting 126 from 140.
Since there are no more digits in the dividend, we add a zero to the remainder making it 140, and continue the process.

On to step 9:
If we divide 140 by 42, we get 3 and a remainder of 14.
Use 3 as the next digit of our solution. 
Result so far: 15297.833
Deduct 126 from 140 and we're left with 14.
Since there are no more digits in the dividend, we add a zero to the remainder making it 140, and continue the process.

The final outcome is 15297.833, with a leftover of 0.0014.