Let's divide 678451 by 2
Let's see how many times 2 fits into 678451.

Let's proceed to step 1:
The number 2 fits into 6 3 times, leaving a remainder of 0.
Use 3 as the next digit of our solution. 
Result so far: 3.0
If we subtract 6 from 6, we get 0.
Fetch the next digit (7) from the dividend, attach it to 0 and continue: 7 / 2

Moving on to step 2:
If we divide 7 by 2, we get 3 and a remainder of 1.
Record the quotient 3 as the next digit in the result. 
Result so far: 33.0
Subtracting 6 from 7 leaves us with 1.
Take the next digit (8) from the dividend and append it to 1, then repeat: 18 / 2

Step 3:
When dividing 18 by 2, we get 9 with a remainder of 0.
The number 9 becomes the next digit in our result. 
Result so far: 339.0
If we take 18 away from 18, we end up with 0.
Grab the next digit (4) from the dividend, add it to 0, then carry on: 4 / 2

Going ahead to step 4:
If we divide 4 by 2, we get 2 and a remainder of 0.
Record the quotient 2 as the next digit in the result. 
Result so far: 3392.0
Subtracting 4 from 4 leaves us with 0.
Append the next digit (5) from the dividend to 0 and continue with: 5 / 2

On to step 5:
When dividing 5 by 2, we get 2 with a remainder of 1.
The number 2 becomes the next digit in our result. 
Result so far: 33922.0
If we take 4 away from 5, we end up with 1.
Bring next digit (1) of the dividend behind the 1 and repeat the process: 11 / 2

Advancing to step 6:
When dividing 11 by 2, we get 5 with a remainder of 1.
Write down 5 as next digit of the result. 
Result so far: 339225.0
If we take 10 away from 11, we end up with 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Advancing to step 7:
2 goes into 10 5 times with a remainder of 0.
The number 5 becomes the next digit in our result. 
Result so far: 339225.5
If we take 10 away from 10, we end up 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.

On to step 8:
2 can be fit into 0 0 times, resulting in a remainder of 0.
Put 0 as the next digit of the answer. 
Result so far: 339225.5
Deduct 0 from 0 and we're left 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.

Step 9:
If we divide 0 by 2, we get 0 and a remainder of 0.
The next digit of our result is 0. 
Result so far: 339225.5
If we take 0 away from 0, we end up 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 339225.5, with a leftover of 0.0.