We look at the division of 42129582 by 124 
We're looking to find how many times 124 goes into 42129582.

Step 1:
The number 124 fits into 4 0 times, leaving a remainder of 4.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Deduct 0 from 4 and we're left with 4.
Fetch the next digit (2) from the dividend, attach it to 4 and continue: 42 / 124

Step 2:
124 can be fit into 42 0 times, resulting in a remainder of 42.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Subtract 0 from 42 to get 42.
Grab the next digit (1) from the dividend, add it to 42, then carry on: 421 / 124

On to step 3:
The number 124 fits into 421 3 times, leaving a remainder of 49.
Write down 3 as next digit of the result. 
Result so far: 3.0
If we take 372 away from 421, we end up with 49.
Grab the next digit (2) from the dividend, add it to 49, then carry on: 492 / 124

Moving on to step 4:
If we divide 492 by 124, we get 3 and a remainder of 120.
The next digit of our result is 3. 
Result so far: 33.0
The remainder is 120 after subtracting 372 from 492.
Fetch the next digit (9) from the dividend, attach it to 120 and continue: 1209 / 124

Advancing to step 5:
If we divide 1209 by 124, we get 9 and a remainder of 93.
Write down 9 as next digit of the result. 
Result so far: 339.0
If we subtract 1116 from 1209, we get 93.
Bring next digit (5) of the dividend behind the 93 and repeat the process: 935 / 124

Going ahead to step 6:
124 can be fit into 935 7 times, resulting in a remainder of 67.
The number 7 becomes the next digit in our result. 
Result so far: 3397.0
If we subtract 868 from 935, we get 67.
Append the next digit (8) from the dividend to 67 and continue with: 678 / 124

Going ahead to step 7:
124 goes into 678 5 times with a remainder of 58.
Use 5 as the next digit of our solution. 
Result so far: 33975.0
Subtracting 620 from 678 leaves us with 58.
Bring next digit (2) of the dividend behind the 58 and repeat the process: 582 / 124

Going ahead to step 8:
The number 124 fits into 582 4 times, leaving a remainder of 86.
Use 4 as the next digit of our solution. 
Result so far: 339754.0
Deduct 496 from 582 and we're left with 86.
Since there are no more digits in the dividend, we add a zero to the remainder making it 860, and continue the process.

Advancing to step 9:
124 goes into 860 6 times with a remainder of 116.
The next digit of our result is 6. 
Result so far: 339754.6
Subtract 744 from 860 to get 116.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1160, and continue the process.

On to step 10:
The number 124 fits into 1160 9 times, leaving a remainder of 44.
The next digit of our result is 9. 
Result so far: 339754.69
If we take 1116 away from 1160, we end up with 44.
Since there are no more digits in the dividend, we add a zero to the remainder making it 440, and continue the process.

Advancing to step 11:
When dividing 440 by 124, we get 3 with a remainder of 68.
Record the quotient 3 as the next digit in the result. 
Result so far: 339754.693
Subtract 372 from 440 to get 68.
Since there are no more digits in the dividend, we add a zero to the remainder making it 680, and continue the process.

Let's proceed to step 12:
124 goes into 680 5 times with a remainder of 60.
The number 5 becomes the next digit in our result. 
Result so far: 339754.6935
If we subtract 620 from 680, we get 60.
Since there are no more digits in the dividend, we add a zero to the remainder making it 600, and continue the process.

Advancing to step 13:
600 divided by 124 is 4 with a remainder of 104.
The next digit of our result is 4. 
Result so far: 339754.69354
If we take 496 away from 600, we end up with 104.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1040, and continue the process.

Going ahead to step 14:
If we divide 1040 by 124, we get 8 and a remainder of 48.
Put 8 as the next digit of the answer. 
Result so far: 339754.693548
Subtracting 992 from 1040 leaves us with 48.
Since there are no more digits in the dividend, we add a zero to the remainder making it 480, and continue the process.

Going ahead to step 15:
480 divided by 124 is 3 with a remainder of 108.
Write down 3 as next digit of the result. 
Result so far: 339754.6935483
Deduct 372 from 480 and we're left with 108.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1080, and continue the process.

Step 16:
When dividing 1080 by 124, we get 8 with a remainder of 88.
The number 8 becomes the next digit in our result. 
Result so far: 339754.69354838
Subtract 992 from 1080 to get 88.
Since there are no more digits in the dividend, we add a zero to the remainder making it 880, and continue the process.

The final result is 339754.69354838 with a remainder of 8.8e-08.