640846 ÷ 42 
We're looking to find how many times 42 goes into 640846.

Going ahead to step 1:
When dividing 6 by 42, we get 0 with a remainder of 6.
Write down 0 as next digit of the result. 
Result so far: 0.0
The remainder is 6 after subtracting 0 from 6.
Bring next digit (4) of the dividend behind the 6 and repeat the process: 64 / 42

Step 2:
42 can be fit into 64 1 times, resulting in a remainder of 22.
The next digit of our result is 1. 
Result so far: 1.0
Subtract 42 from 64 to get 22.
Include the next digit (0) from the dividend after 22, then repeat: 220 / 42

Step 3:
When dividing 220 by 42, we get 5 with a remainder of 10.
Put 5 as the next digit of the answer. 
Result so far: 15.0
Subtract 210 from 220 to get 10.
Grab the next digit (8) from the dividend, add it to 10, then carry on: 108 / 42

Step 4:
42 goes into 108 2 times with a remainder of 24.
Write down 2 as next digit of the result. 
Result so far: 152.0
The remainder is 24 after subtracting 84 from 108.
Append the next digit (4) from the dividend to 24 and continue with: 244 / 42

Going ahead to step 5:
If we divide 244 by 42, we get 5 and a remainder of 34.
Put 5 as the next digit of the answer. 
Result so far: 1525.0
If we subtract 210 from 244, we get 34.
Append the next digit (6) from the dividend to 34 and continue with: 346 / 42

Advancing to step 6:
The number 42 fits into 346 8 times, leaving a remainder of 10.
Record the quotient 8 as the next digit in the result. 
Result so far: 15258.0
Subtract 336 from 346 to get 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Step 7:
When dividing 100 by 42, we get 2 with a remainder of 16.
Write down 2 as next digit of the result. 
Result so far: 15258.2
Subtracting 84 from 100 leaves us with 16.
Since there are no more digits in the dividend, we add a zero to the remainder making it 160, and continue the process.

Moving on to step 8:
When dividing 160 by 42, we get 3 with a remainder of 34.
The next digit of our result is 3. 
Result so far: 15258.23
If we take 126 away from 160, we end up with 34.
Since there are no more digits in the dividend, we add a zero to the remainder making it 340, and continue the process.

Let's proceed to step 9:
42 can be fit into 340 8 times, resulting in a remainder of 4.
Record the quotient 8 as the next digit in the result. 
Result so far: 15258.238
If we subtract 336 from 340, we get 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Moving on to step 10:
When dividing 40 by 42, we get 0 with a remainder of 40.
The number 0 becomes the next digit in our result. 
Result so far: 15258.238
If we subtract 0 from 40, we get 40.
Since there are no more digits in the dividend, we add a zero to the remainder making it 400, and continue the process.

Let's proceed to step 11:
42 goes into 400 9 times with a remainder of 22.
The next digit of our result is 9. 
Result so far: 15258.23809
Subtract 378 from 400 to get 22.
Since there are no more digits in the dividend, we add a zero to the remainder making it 220, and continue the process.

Moving on to step 12:
42 goes into 220 5 times with a remainder of 10.
The next digit of our result is 5. 
Result so far: 15258.238095
Subtract 210 from 220 to get 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Step 13:
42 can be fit into 100 2 times, resulting in a remainder of 16.
Use 2 as the next digit of our solution. 
Result so far: 15258.2380952
Subtract 84 from 100 to get 16.
Since there are no more digits in the dividend, we add a zero to the remainder making it 160, and continue the process.

Let's proceed to step 14:
When dividing 160 by 42, we get 3 with a remainder of 34.
Record the quotient 3 as the next digit in the result. 
Result so far: 15258.23809523
Subtracting 126 from 160 leaves us with 34.
Since there are no more digits in the dividend, we add a zero to the remainder making it 340, and continue the process.

The final outcome is 15258.23809523, with a leftover of 3.4e-08.