We're dividing 159821 by 40 
We're looking to find how many times 40 goes into 159821.

Let's proceed to step 1:
1 divided by 40 is 0 with a remainder of 1.
Write down 0 as next digit of the result. 
Result so far: 0.0
Subtract 0 from 1 to get 1.
Take the next digit (5) from the dividend and append it to 1, then repeat: 15 / 40

Advancing to step 2:
15 divided by 40 is 0 with a remainder of 15.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
The remainder is 15 after subtracting 0 from 15.
Take the next digit (9) from the dividend and append it to 15, then repeat: 159 / 40

Moving on to step 3:
The number 40 fits into 159 3 times, leaving a remainder of 39.
The next digit of our result is 3. 
Result so far: 3.0
Deduct 120 from 159 and we're left with 39.
Append the next digit (8) from the dividend to 39 and continue with: 398 / 40

Step 4:
If we divide 398 by 40, we get 9 and a remainder of 38.
Record the quotient 9 as the next digit in the result. 
Result so far: 39.0
Subtracting 360 from 398 leaves us with 38.
Include the next digit (2) from the dividend after 38, then repeat: 382 / 40

Step 5:
The number 40 fits into 382 9 times, leaving a remainder of 22.
The number 9 becomes the next digit in our result. 
Result so far: 399.0
If we subtract 360 from 382, we get 22.
Grab the next digit (1) from the dividend, add it to 22, then carry on: 221 / 40

Advancing to step 6:
40 can be fit into 221 5 times, resulting in a remainder of 21.
Record the quotient 5 as the next digit in the result. 
Result so far: 3995.0
The remainder is 21 after subtracting 200 from 221.
Since there are no more digits in the dividend, we add a zero to the remainder making it 210, and continue the process.

Let's proceed to step 7:
40 goes into 210 5 times with a remainder of 10.
The next digit of our result is 5. 
Result so far: 3995.5
Deduct 200 from 210 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.

Moving on to step 8:
40 goes into 100 2 times with a remainder of 20.
Put 2 as the next digit of the answer. 
Result so far: 3995.52
Deduct 80 from 100 and we're left with 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

On to step 9:
40 can be fit into 200 5 times, resulting in a remainder of 0.
Put 5 as the next digit of the answer. 
Result so far: 3995.525
If we subtract 200 from 200, 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 10:
If we divide 0 by 40, we get 0 and a remainder of 0.
The next digit of our result is 0. 
Result so far: 3995.525
If we take 0 away from 0, 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.

Going ahead to step 11:
0 divided by 40 is 0 with a remainder of 0.
The number 0 becomes the next digit in our result. 
Result so far: 3995.525
The remainder is 0 after subtracting 0 from 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 3995.525, and the remainder is 0.0.