Let's divide 851321 by 2
We're looking to find how many times 2 goes into 851321.

Going ahead to step 1:
2 goes into 8 4 times with a remainder of 0.
Use 4 as the next digit of our solution. 
Result so far: 4.0
The remainder is 0 after subtracting 8 from 8.
Include the next digit (5) from the dividend after 0, then repeat: 5 / 2

Let's proceed to step 2:
2 can be fit into 5 2 times, resulting in a remainder of 1.
The number 2 becomes the next digit in our result. 
Result so far: 42.0
If we take 4 away from 5, we end up with 1.
Take the next digit (1) from the dividend and append it to 1, then repeat: 11 / 2

Step 3:
If we divide 11 by 2, we get 5 and a remainder of 1.
Record the quotient 5 as the next digit in the result. 
Result so far: 425.0
Subtract 10 from 11 to get 1.
Append the next digit (3) from the dividend to 1 and continue with: 13 / 2

Step 4:
When dividing 13 by 2, we get 6 with a remainder of 1.
The number 6 becomes the next digit in our result. 
Result so far: 4256.0
Subtract 12 from 13 to get 1.
Include the next digit (2) from the dividend after 1, then repeat: 12 / 2

Going ahead to step 5:
2 goes into 12 6 times with a remainder of 0.
Use 6 as the next digit of our solution. 
Result so far: 42566.0
If we take 12 away from 12, we end up with 0.
Grab the next digit (1) from the dividend, add it to 0, then carry on: 1 / 2

Advancing to step 6:
If we divide 1 by 2, we get 0 and a remainder of 1.
Use 0 as the next digit of our solution. 
Result so far: 425660.0
If we subtract 0 from 1, we get 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Going ahead to step 7:
10 divided by 2 is 5 with a remainder of 0.
The next digit of our result is 5. 
Result so far: 425660.5
Subtract 10 from 10 to get 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Advancing to step 8:
The number 2 fits into 0 0 times, leaving a remainder of 0.
Put 0 as the next digit of the answer. 
Result so far: 425660.5
The remainder is 0 after subtracting 0 from 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

On to step 9:
When dividing 0 by 2, we get 0 with a remainder of 0.
The number 0 becomes the next digit in our result. 
Result so far: 425660.5
Subtracting 0 from 0 leaves us with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

The final outcome is 425660.5, with a leftover of 0.0.