We divide 135156 by 21
Let's see how many times 21 fits into 135156.

Going ahead to step 1:
If we divide 1 by 21, we get 0 and a remainder of 1.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Deduct 0 from 1 and we're left with 1.
Grab the next digit (3) from the dividend, add it to 1, then carry on: 13 / 21

Going ahead to step 2:
If we divide 13 by 21, we get 0 and a remainder of 13.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Deduct 0 from 13 and we're left with 13.
Fetch the next digit (5) from the dividend, attach it to 13 and continue: 135 / 21

Going ahead to step 3:
21 goes into 135 6 times with a remainder of 9.
The next digit of our result is 6. 
Result so far: 6.0
Subtract 126 from 135 to get 9.
Bring next digit (1) of the dividend behind the 9 and repeat the process: 91 / 21

Going ahead to step 4:
When dividing 91 by 21, we get 4 with a remainder of 7.
Put 4 as the next digit of the answer. 
Result so far: 64.0
Deduct 84 from 91 and we're left with 7.
Include the next digit (5) from the dividend after 7, then repeat: 75 / 21

Going ahead to step 5:
When dividing 75 by 21, we get 3 with a remainder of 12.
Put 3 as the next digit of the answer. 
Result so far: 643.0
Subtracting 63 from 75 leaves us with 12.
Include the next digit (6) from the dividend after 12, then repeat: 126 / 21

Going ahead to step 6:
When dividing 126 by 21, we get 6 with a remainder of 0.
Write down 6 as next digit of the result. 
Result so far: 6436.0
The remainder is 0 after subtracting 126 from 126.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Let's proceed to step 7:
If we divide 0 by 21, we get 0 and a remainder of 0.
The number 0 becomes the next digit in our result. 
Result so far: 6436.0
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.

Moving on to step 8:
The number 21 fits into 0 0 times, leaving a remainder of 0.
The next digit of our result is 0. 
Result so far: 6436.0
Subtracting 0 from 0 leaves us 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.

The quotient of the division is 6436.0, and the remainder is 0.0.