We're dividing 126399 by 8 
We want to figure out the number of times 126399 can be divided by 8.

Moving on to step 1:
When dividing 1 by 8, we get 0 with a remainder of 1.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Subtracting 0 from 1 leaves us with 1.
Grab the next digit (2) from the dividend, add it to 1, then carry on: 12 / 8

Going ahead to step 2:
If we divide 12 by 8, we get 1 and a remainder of 4.
Write down 1 as next digit of the result. 
Result so far: 1.0
Subtracting 8 from 12 leaves us with 4.
Take the next digit (6) from the dividend and append it to 4, then repeat: 46 / 8

On to step 3:
The number 8 fits into 46 5 times, leaving a remainder of 6.
Put 5 as the next digit of the answer. 
Result so far: 15.0
If we take 40 away from 46, we end up with 6.
Grab the next digit (3) from the dividend, add it to 6, then carry on: 63 / 8

Step 4:
If we divide 63 by 8, we get 7 and a remainder of 7.
Use 7 as the next digit of our solution. 
Result so far: 157.0
The remainder is 7 after subtracting 56 from 63.
Fetch the next digit (9) from the dividend, attach it to 7 and continue: 79 / 8

Moving on to step 5:
When dividing 79 by 8, we get 9 with a remainder of 7.
The next digit of our result is 9. 
Result so far: 1579.0
If we take 72 away from 79, we end up with 7.
Grab the next digit (9) from the dividend, add it to 7, then carry on: 79 / 8

Advancing to step 6:
If we divide 79 by 8, we get 9 and a remainder of 7.
Write down 9 as next digit of the result. 
Result so far: 15799.0
The remainder is 7 after subtracting 72 from 79.
Since there are no more digits in the dividend, we add a zero to the remainder making it 70, and continue the process.

Moving on to step 7:
70 divided by 8 is 8 with a remainder of 6.
Use 8 as the next digit of our solution. 
Result so far: 15799.8
Subtract 64 from 70 to get 6.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

Step 8:
If we divide 60 by 8, we get 7 and a remainder of 4.
Put 7 as the next digit of the answer. 
Result so far: 15799.87
Subtracting 56 from 60 leaves us 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.

Going ahead to step 9:
8 can be fit into 40 5 times, resulting in a remainder of 0.
The next digit of our result is 5. 
Result so far: 15799.875
Subtracting 40 from 40 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.

On to step 10:
8 can be fit into 0 0 times, resulting in a remainder of 0.
The number 0 becomes the next digit in our result. 
Result so far: 15799.875
If we subtract 0 from 0, we 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.

Going ahead to step 11:
8 can be fit into 0 0 times, resulting in a remainder of 0.
The next digit of our result is 0. 
Result so far: 15799.875
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.

The quotient of the division is 15799.875, and the remainder is 0.0.