42578344 divided by 642 
We want to figure out the number of times 42578344 can be divided by 642.

On to step 1:
If we divide 4 by 642, we get 0 and a remainder of 4.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Deduct 0 from 4 and we're left with 4.
Grab the next digit (2) from the dividend, add it to 4, then carry on: 42 / 642

On to step 2:
When dividing 42 by 642, we get 0 with a remainder of 42.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtract 0 from 42 to get 42.
Bring next digit (5) of the dividend behind the 42 and repeat the process: 425 / 642

Moving on to step 3:
The number 642 fits into 425 0 times, leaving a remainder of 425.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtract 0 from 425 to get 425.
Grab the next digit (7) from the dividend, add it to 425, then carry on: 4257 / 642

On to step 4:
4257 divided by 642 is 6 with a remainder of 405.
Use 6 as the next digit of our solution. 
Result so far: 6.0
Subtract 3852 from 4257 to get 405.
Grab the next digit (8) from the dividend, add it to 405, then carry on: 4058 / 642

On to step 5:
If we divide 4058 by 642, we get 6 and a remainder of 206.
Write down 6 as next digit of the result. 
Result so far: 66.0
Subtracting 3852 from 4058 leaves us with 206.
Take the next digit (3) from the dividend and append it to 206, then repeat: 2063 / 642

Step 6:
642 goes into 2063 3 times with a remainder of 137.
Use 3 as the next digit of our solution. 
Result so far: 663.0
Deduct 1926 from 2063 and we're left with 137.
Take the next digit (4) from the dividend and append it to 137, then repeat: 1374 / 642

Let's proceed to step 7:
When dividing 1374 by 642, we get 2 with a remainder of 90.
Write down 2 as next digit of the result. 
Result so far: 6632.0
Subtract 1284 from 1374 to get 90.
Grab the next digit (4) from the dividend, add it to 90, then carry on: 904 / 642

Let's proceed to step 8:
If we divide 904 by 642, we get 1 and a remainder of 262.
Put 1 as the next digit of the answer. 
Result so far: 66321.0
The remainder is 262 after subtracting 642 from 904.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2620, and continue the process.

Going ahead to step 9:
642 goes into 2620 4 times with a remainder of 52.
Use 4 as the next digit of our solution. 
Result so far: 66321.4
The remainder is 52 after subtracting 2568 from 2620.
Since there are no more digits in the dividend, we add a zero to the remainder making it 520, and continue the process.

Step 10:
642 can be fit into 520 0 times, resulting in a remainder of 520.
Record the quotient 0 as the next digit in the result. 
Result so far: 66321.4
The remainder is 520 after subtracting 0 from 520.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5200, and continue the process.

Step 11:
5200 divided by 642 is 8 with a remainder of 64.
Write down 8 as next digit of the result. 
Result so far: 66321.408
Deduct 5136 from 5200 and we're left with 64.
Since there are no more digits in the dividend, we add a zero to the remainder making it 640, and continue the process.

Advancing to step 12:
The number 642 fits into 640 0 times, leaving a remainder of 640.
Put 0 as the next digit of the answer. 
Result so far: 66321.408
Subtracting 0 from 640 leaves us with 640.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6400, and continue the process.

Going ahead to step 13:
The number 642 fits into 6400 9 times, leaving a remainder of 622.
The number 9 becomes the next digit in our result. 
Result so far: 66321.40809
Subtract 5778 from 6400 to get 622.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6220, and continue the process.

On to step 14:
642 can be fit into 6220 9 times, resulting in a remainder of 442.
The next digit of our result is 9. 
Result so far: 66321.408099
The remainder is 442 after subtracting 5778 from 6220.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4420, and continue the process.

After the division, we end up with 66321.408099 and a remainder of 4.42e-05.