We're dividing 286335 by 21 
We want to figure out the number of times 286335 can be divided by 21.

Step 1:
21 goes into 2 0 times with a remainder of 2.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Deduct 0 from 2 and we're left with 2.
Include the next digit (8) from the dividend after 2, then repeat: 28 / 21

On to step 2:
28 divided by 21 is 1 with a remainder of 7.
The number 1 becomes the next digit in our result. 
Result so far: 1.0
The remainder is 7 after subtracting 21 from 28.
Fetch the next digit (6) from the dividend, attach it to 7 and continue: 76 / 21

On to step 3:
76 divided by 21 is 3 with a remainder of 13.
Record the quotient 3 as the next digit in the result. 
Result so far: 13.0
If we take 63 away from 76, we end up with 13.
Bring next digit (3) of the dividend behind the 13 and repeat the process: 133 / 21

Let's proceed to step 4:
21 goes into 133 6 times with a remainder of 7.
Record the quotient 6 as the next digit in the result. 
Result so far: 136.0
Subtract 126 from 133 to get 7.
Bring next digit (3) of the dividend behind the 7 and repeat the process: 73 / 21

On to step 5:
73 divided by 21 is 3 with a remainder of 10.
Put 3 as the next digit of the answer. 
Result so far: 1363.0
Deduct 63 from 73 and we're left with 10.
Include the next digit (5) from the dividend after 10, then repeat: 105 / 21

Going ahead to step 6:
105 divided by 21 is 5 with a remainder of 0.
The number 5 becomes the next digit in our result. 
Result so far: 13635.0
Subtract 105 from 105 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.

Moving on to step 7:
The number 21 fits into 0 0 times, leaving a remainder of 0.
Use 0 as the next digit of our solution. 
Result so far: 13635.0
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.

Advancing to step 8:
The number 21 fits into 0 0 times, leaving a remainder of 0.
Write down 0 as next digit of the result. 
Result so far: 13635.0
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 13635.0, and the remainder is 0.0.