We divide 42450991 by 646
Our goal is to divide 42450991 by 646.

On to step 1:
If we divide 4 by 646, we get 0 and a remainder of 4.
The next digit of our result is 0. 
Result so far: 0.0
Subtracting 0 from 4 leaves us with 4.
Fetch the next digit (2) from the dividend, attach it to 4 and continue: 42 / 646

On to step 2:
646 can be fit into 42 0 times, resulting in a remainder of 42.
Use 0 as the next digit of our solution. 
Result so far: 0.0
The remainder is 42 after subtracting 0 from 42.
Fetch the next digit (4) from the dividend, attach it to 42 and continue: 424 / 646

On to step 3:
646 goes into 424 0 times with a remainder of 424.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we subtract 0 from 424, we get 424.
Append the next digit (5) from the dividend to 424 and continue with: 4245 / 646

Step 4:
The number 646 fits into 4245 6 times, leaving a remainder of 369.
The next digit of our result is 6. 
Result so far: 6.0
Subtracting 3876 from 4245 leaves us with 369.
Take the next digit (0) from the dividend and append it to 369, then repeat: 3690 / 646

Moving on to step 5:
646 can be fit into 3690 5 times, resulting in a remainder of 460.
Use 5 as the next digit of our solution. 
Result so far: 65.0
If we subtract 3230 from 3690, we get 460.
Take the next digit (9) from the dividend and append it to 460, then repeat: 4609 / 646

Step 6:
4609 divided by 646 is 7 with a remainder of 87.
The number 7 becomes the next digit in our result. 
Result so far: 657.0
The remainder is 87 after subtracting 4522 from 4609.
Append the next digit (9) from the dividend to 87 and continue with: 879 / 646

On to step 7:
When dividing 879 by 646, we get 1 with a remainder of 233.
The next digit of our result is 1. 
Result so far: 6571.0
Subtracting 646 from 879 leaves us with 233.
Include the next digit (1) from the dividend after 233, then repeat: 2331 / 646

Step 8:
646 goes into 2331 3 times with a remainder of 393.
Use 3 as the next digit of our solution. 
Result so far: 65713.0
If we subtract 1938 from 2331, we get 393.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3930, and continue the process.

Going ahead to step 9:
3930 divided by 646 is 6 with a remainder of 54.
Record the quotient 6 as the next digit in the result. 
Result so far: 65713.6
If we take 3876 away from 3930, we end up with 54.
Since there are no more digits in the dividend, we add a zero to the remainder making it 540, and continue the process.

On to step 10:
When dividing 540 by 646, we get 0 with a remainder of 540.
Put 0 as the next digit of the answer. 
Result so far: 65713.6
If we take 0 away from 540, we end up with 540.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5400, and continue the process.

Advancing to step 11:
The number 646 fits into 5400 8 times, leaving a remainder of 232.
Use 8 as the next digit of our solution. 
Result so far: 65713.608
Deduct 5168 from 5400 and we're left with 232.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2320, and continue the process.

Step 12:
646 can be fit into 2320 3 times, resulting in a remainder of 382.
Record the quotient 3 as the next digit in the result. 
Result so far: 65713.6083
Subtracting 1938 from 2320 leaves us with 382.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3820, and continue the process.

Moving on to step 13:
646 can be fit into 3820 5 times, resulting in a remainder of 590.
Record the quotient 5 as the next digit in the result. 
Result so far: 65713.60835
Subtract 3230 from 3820 to get 590.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5900, and continue the process.

Advancing to step 14:
If we divide 5900 by 646, we get 9 and a remainder of 86.
Use 9 as the next digit of our solution. 
Result so far: 65713.608359
If we subtract 5814 from 5900, we get 86.
Since there are no more digits in the dividend, we add a zero to the remainder making it 860, and continue the process.

Moving on to step 15:
646 goes into 860 1 times with a remainder of 214.
Put 1 as the next digit of the answer. 
Result so far: 65713.6083591
Subtracting 646 from 860 leaves us with 214.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2140, and continue the process.

Advancing to step 16:
646 goes into 2140 3 times with a remainder of 202.
The next digit of our result is 3. 
Result so far: 65713.60835913
Deduct 1938 from 2140 and we're left with 202.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2020, and continue the process.

The final outcome is 65713.60835913, with a leftover of 2.02e-07.