We're dividing 13579040 by 12 
We want to divide 13579040 by 12.

On to step 1:
The number 12 fits into 1 0 times, leaving a remainder of 1.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we take 0 away from 1, we end up with 1.
Grab the next digit (3) from the dividend, add it to 1, then carry on: 13 / 12

Advancing to step 2:
12 goes into 13 1 times with a remainder of 1.
Put 1 as the next digit of the answer. 
Result so far: 1.0
Subtracting 12 from 13 leaves us with 1.
Grab the next digit (5) from the dividend, add it to 1, then carry on: 15 / 12

Step 3:
12 can be fit into 15 1 times, resulting in a remainder of 3.
Use 1 as the next digit of our solution. 
Result so far: 11.0
Subtracting 12 from 15 leaves us with 3.
Grab the next digit (7) from the dividend, add it to 3, then carry on: 37 / 12

Moving on to step 4:
37 divided by 12 is 3 with a remainder of 1.
Put 3 as the next digit of the answer. 
Result so far: 113.0
If we take 36 away from 37, we end up with 1.
Fetch the next digit (9) from the dividend, attach it to 1 and continue: 19 / 12

On to step 5:
19 divided by 12 is 1 with a remainder of 7.
The number 1 becomes the next digit in our result. 
Result so far: 1131.0
Deduct 12 from 19 and we're left with 7.
Append the next digit (0) from the dividend to 7 and continue with: 70 / 12

On to step 6:
70 divided by 12 is 5 with a remainder of 10.
Use 5 as the next digit of our solution. 
Result so far: 11315.0
Subtract 60 from 70 to get 10.
Append the next digit (4) from the dividend to 10 and continue with: 104 / 12

Step 7:
If we divide 104 by 12, we get 8 and a remainder of 8.
Use 8 as the next digit of our solution. 
Result so far: 113158.0
Deduct 96 from 104 and we're left with 8.
Bring next digit (0) of the dividend behind the 8 and repeat the process: 80 / 12

On to step 8:
12 goes into 80 6 times with a remainder of 8.
Write down 6 as next digit of the result. 
Result so far: 1131586.0
Deduct 72 from 80 and we're left with 8.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

Let's proceed to step 9:
12 goes into 80 6 times with a remainder of 8.
The number 6 becomes the next digit in our result. 
Result so far: 1131586.6
If we take 72 away from 80, we end up with 8.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

Advancing to step 10:
The number 12 fits into 80 6 times, leaving a remainder of 8.
The number 6 becomes the next digit in our result. 
Result so far: 1131586.66
Subtracting 72 from 80 leaves us with 8.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

The final outcome is 1131586.66, with a leftover of 0.008.