686638 divided by 12 
We want to figure out the number of times 686638 can be divided by 12.

Advancing to step 1:
When dividing 6 by 12, we get 0 with a remainder of 6.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtracting 0 from 6 leaves us with 6.
Fetch the next digit (8) from the dividend, attach it to 6 and continue: 68 / 12

Moving on to step 2:
The number 12 fits into 68 5 times, leaving a remainder of 8.
Put 5 as the next digit of the answer. 
Result so far: 5.0
Subtract 60 from 68 to get 8.
Append the next digit (6) from the dividend to 8 and continue with: 86 / 12

Advancing to step 3:
12 goes into 86 7 times with a remainder of 2.
Put 7 as the next digit of the answer. 
Result so far: 57.0
Subtracting 84 from 86 leaves us with 2.
Take the next digit (6) from the dividend and append it to 2, then repeat: 26 / 12

Step 4:
12 can be fit into 26 2 times, resulting in a remainder of 2.
The number 2 becomes the next digit in our result. 
Result so far: 572.0
The remainder is 2 after subtracting 24 from 26.
Fetch the next digit (3) from the dividend, attach it to 2 and continue: 23 / 12

Going ahead to step 5:
12 can be fit into 23 1 times, resulting in a remainder of 11.
The number 1 becomes the next digit in our result. 
Result so far: 5721.0
Deduct 12 from 23 and we're left with 11.
Bring next digit (8) of the dividend behind the 11 and repeat the process: 118 / 12

Advancing to step 6:
12 goes into 118 9 times with a remainder of 10.
The next digit of our result is 9. 
Result so far: 57219.0
If we take 108 away from 118, we end up with 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 12, we get 8 with a remainder of 4.
The number 8 becomes the next digit in our result. 
Result so far: 57219.8
If we subtract 96 from 100, 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 8:
The number 12 fits into 40 3 times, leaving a remainder of 4.
Use 3 as the next digit of our solution. 
Result so far: 57219.83
Deduct 36 from 40 and we're left with 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Step 9:
If we divide 40 by 12, we get 3 and a remainder of 4.
Put 3 as the next digit of the answer. 
Result so far: 57219.833
The remainder is 4 after subtracting 36 from 40.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Our division results in 57219.833 with a remaining 0.0004.