We look at the division of 421445 by 12 
We want to figure out the number of times 421445 can be divided by 12.

Going ahead to step 1:
12 goes into 4 0 times with a remainder of 4.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we take 0 away from 4, we end up with 4.
Fetch the next digit (2) from the dividend, attach it to 4 and continue: 42 / 12

On to step 2:
12 goes into 42 3 times with a remainder of 6.
Put 3 as the next digit of the answer. 
Result so far: 3.0
Deduct 36 from 42 and we're left with 6.
Fetch the next digit (1) from the dividend, attach it to 6 and continue: 61 / 12

Let's proceed to step 3:
61 divided by 12 is 5 with a remainder of 1.
Write down 5 as next digit of the result. 
Result so far: 35.0
Subtracting 60 from 61 leaves us with 1.
Bring next digit (4) of the dividend behind the 1 and repeat the process: 14 / 12

Moving on to step 4:
12 goes into 14 1 times with a remainder of 2.
Record the quotient 1 as the next digit in the result. 
Result so far: 351.0
If we take 12 away from 14, we end up with 2.
Append the next digit (4) from the dividend to 2 and continue with: 24 / 12

Advancing to step 5:
24 divided by 12 is 2 with a remainder of 0.
Put 2 as the next digit of the answer. 
Result so far: 3512.0
If we subtract 24 from 24, we get 0.
Fetch the next digit (5) from the dividend, attach it to 0 and continue: 5 / 12

On to step 6:
12 can be fit into 5 0 times, resulting in a remainder of 5.
Write down 0 as next digit of the result. 
Result so far: 35120.0
If we take 0 away from 5, we end up with 5.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

Moving on to step 7:
12 can be fit into 50 4 times, resulting in a remainder of 2.
Record the quotient 4 as the next digit in the result. 
Result so far: 35120.4
Deduct 48 from 50 and we're left with 2.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

Let's proceed to step 8:
The number 12 fits into 20 1 times, leaving a remainder of 8.
Record the quotient 1 as the next digit in the result. 
Result so far: 35120.41
Deduct 12 from 20 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:
When dividing 80 by 12, we get 6 with a remainder of 8.
Put 6 as the next digit of the answer. 
Result so far: 35120.416
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 10:
12 goes into 80 6 times with a remainder of 8.
Use 6 as the next digit of our solution. 
Result so far: 35120.4166
Subtract 72 from 80 to get 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 35120.4166, with a leftover of 8e-05.