123240 ÷ 42 
Let's see how many times 42 fits into 123240.

Advancing to step 1:
42 goes into 1 0 times with a remainder of 1.
The next digit of our result is 0. 
Result so far: 0.0
Subtract 0 from 1 to get 1.
Take the next digit (2) from the dividend and append it to 1, then repeat: 12 / 42

Going ahead to step 2:
The number 42 fits into 12 0 times, leaving a remainder of 12.
Write down 0 as next digit of the result. 
Result so far: 0.0
The remainder is 12 after subtracting 0 from 12.
Bring next digit (3) of the dividend behind the 12 and repeat the process: 123 / 42

Let's proceed to step 3:
42 goes into 123 2 times with a remainder of 39.
Record the quotient 2 as the next digit in the result. 
Result so far: 2.0
Subtract 84 from 123 to get 39.
Take the next digit (2) from the dividend and append it to 39, then repeat: 392 / 42

Step 4:
When dividing 392 by 42, we get 9 with a remainder of 14.
Use 9 as the next digit of our solution. 
Result so far: 29.0
If we take 378 away from 392, we end up with 14.
Include the next digit (4) from the dividend after 14, then repeat: 144 / 42

Going ahead to step 5:
If we divide 144 by 42, we get 3 and a remainder of 18.
Use 3 as the next digit of our solution. 
Result so far: 293.0
If we subtract 126 from 144, we get 18.
Include the next digit (0) from the dividend after 18, then repeat: 180 / 42

On to step 6:
42 goes into 180 4 times with a remainder of 12.
The number 4 becomes the next digit in our result. 
Result so far: 2934.0
Deduct 168 from 180 and we're left with 12.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

Step 7:
The number 42 fits into 120 2 times, leaving a remainder of 36.
Put 2 as the next digit of the answer. 
Result so far: 2934.2
Subtracting 84 from 120 leaves us with 36.
Since there are no more digits in the dividend, we add a zero to the remainder making it 360, and continue the process.

Step 8:
360 divided by 42 is 8 with a remainder of 24.
Write down 8 as next digit of the result. 
Result so far: 2934.28
Subtracting 336 from 360 leaves us with 24.
Since there are no more digits in the dividend, we add a zero to the remainder making it 240, and continue the process.

On to step 9:
42 can be fit into 240 5 times, resulting in a remainder of 30.
Record the quotient 5 as the next digit in the result. 
Result so far: 2934.285
The remainder is 30 after subtracting 210 from 240.
Since there are no more digits in the dividend, we add a zero to the remainder making it 300, and continue the process.

Let's proceed to step 10:
300 divided by 42 is 7 with a remainder of 6.
The number 7 becomes the next digit in our result. 
Result so far: 2934.2857
Subtract 294 from 300 to get 6.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

Moving on to step 11:
60 divided by 42 is 1 with a remainder of 18.
Write down 1 as next digit of the result. 
Result so far: 2934.28571
If we take 42 away from 60, we end up with 18.
Since there are no more digits in the dividend, we add a zero to the remainder making it 180, and continue the process.

Let's proceed to step 12:
180 divided by 42 is 4 with a remainder of 12.
Put 4 as the next digit of the answer. 
Result so far: 2934.285714
If we subtract 168 from 180, we get 12.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

On to step 13:
The number 42 fits into 120 2 times, leaving a remainder of 36.
Record the quotient 2 as the next digit in the result. 
Result so far: 2934.2857142
If we subtract 84 from 120, we get 36.
Since there are no more digits in the dividend, we add a zero to the remainder making it 360, and continue the process.

Advancing to step 14:
If we divide 360 by 42, we get 8 and a remainder of 24.
The number 8 becomes the next digit in our result. 
Result so far: 2934.28571428
Deduct 336 from 360 and we're left with 24.
Since there are no more digits in the dividend, we add a zero to the remainder making it 240, and continue the process.

The final result is 2934.28571428 with a remainder of 2.4e-08.