We're dividing 420153 by 40 
Our goal is to divide 420153 by 40.

Going ahead to step 1:
4 divided by 40 is 0 with a remainder of 4.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Deduct 0 from 4 and we're left with 4.
Include the next digit (2) from the dividend after 4, then repeat: 42 / 40

Advancing to step 2:
42 divided by 40 is 1 with a remainder of 2.
The next digit of our result is 1. 
Result so far: 1.0
If we take 40 away from 42, we end up with 2.
Include the next digit (0) from the dividend after 2, then repeat: 20 / 40

Step 3:
The number 40 fits into 20 0 times, leaving a remainder of 20.
Put 0 as the next digit of the answer. 
Result so far: 10.0
Subtract 0 from 20 to get 20.
Fetch the next digit (1) from the dividend, attach it to 20 and continue: 201 / 40

Let's proceed to step 4:
When dividing 201 by 40, we get 5 with a remainder of 1.
Put 5 as the next digit of the answer. 
Result so far: 105.0
If we subtract 200 from 201, we get 1.
Bring next digit (5) of the dividend behind the 1 and repeat the process: 15 / 40

On to step 5:
15 divided by 40 is 0 with a remainder of 15.
The next digit of our result is 0. 
Result so far: 1050.0
If we subtract 0 from 15, we get 15.
Append the next digit (3) from the dividend to 15 and continue with: 153 / 40

On to step 6:
When dividing 153 by 40, we get 3 with a remainder of 33.
The number 3 becomes the next digit in our result. 
Result so far: 10503.0
If we take 120 away from 153, we end up with 33.
Since there are no more digits in the dividend, we add a zero to the remainder making it 330, and continue the process.

Let's proceed to step 7:
330 divided by 40 is 8 with a remainder of 10.
The next digit of our result is 8. 
Result so far: 10503.8
Deduct 320 from 330 and we're left 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.

Advancing to step 8:
100 divided by 40 is 2 with a remainder of 20.
Write down 2 as next digit of the result. 
Result so far: 10503.82
If we subtract 80 from 100, we get 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

Let's proceed to step 9:
40 can be fit into 200 5 times, resulting in a remainder of 0.
The number 5 becomes the next digit in our result. 
Result so far: 10503.825
If we take 200 away from 200, 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 10:
If we divide 0 by 40, we get 0 and a remainder of 0.
Record the quotient 0 as the next digit in the result. 
Result so far: 10503.825
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.

Step 11:
The number 40 fits into 0 0 times, leaving a remainder of 0.
Record the quotient 0 as the next digit in the result. 
Result so far: 10503.825
Subtract 0 from 0 to 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.

After the division, we end up with 10503.825 and a remainder of 0.0.