We're dividing 153085 by 21 
Let's see how many times 21 fits into 153085.

Step 1:
1 divided by 21 is 0 with a remainder of 1.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtracting 0 from 1 leaves us with 1.
Fetch the next digit (5) from the dividend, attach it to 1 and continue: 15 / 21

Step 2:
21 goes into 15 0 times with a remainder of 15.
Write down 0 as next digit of the result. 
Result so far: 0.0
Subtracting 0 from 15 leaves us with 15.
Fetch the next digit (3) from the dividend, attach it to 15 and continue: 153 / 21

Let's proceed to step 3:
The number 21 fits into 153 7 times, leaving a remainder of 6.
Record the quotient 7 as the next digit in the result. 
Result so far: 7.0
If we subtract 147 from 153, we get 6.
Append the next digit (0) from the dividend to 6 and continue with: 60 / 21

Let's proceed to step 4:
The number 21 fits into 60 2 times, leaving a remainder of 18.
The next digit of our result is 2. 
Result so far: 72.0
If we subtract 42 from 60, we get 18.
Append the next digit (8) from the dividend to 18 and continue with: 188 / 21

Let's proceed to step 5:
21 goes into 188 8 times with a remainder of 20.
Put 8 as the next digit of the answer. 
Result so far: 728.0
Subtract 168 from 188 to get 20.
Fetch the next digit (5) from the dividend, attach it to 20 and continue: 205 / 21

Let's proceed to step 6:
21 goes into 205 9 times with a remainder of 16.
Put 9 as the next digit of the answer. 
Result so far: 7289.0
Subtract 189 from 205 to get 16.
Since there are no more digits in the dividend, we add a zero to the remainder making it 160, and continue the process.

Going ahead to step 7:
21 goes into 160 7 times with a remainder of 13.
The number 7 becomes the next digit in our result. 
Result so far: 7289.7
If we take 147 away from 160, we end up with 13.
Since there are no more digits in the dividend, we add a zero to the remainder making it 130, and continue the process.

Step 8:
21 can be fit into 130 6 times, resulting in a remainder of 4.
Write down 6 as next digit of the result. 
Result so far: 7289.76
If we take 126 away from 130, we end up with 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Moving on to step 9:
The number 21 fits into 40 1 times, leaving a remainder of 19.
The next digit of our result is 1. 
Result so far: 7289.761
If we subtract 21 from 40, we get 19.
Since there are no more digits in the dividend, we add a zero to the remainder making it 190, and continue the process.

Step 10:
The number 21 fits into 190 9 times, leaving a remainder of 1.
The next digit of our result is 9. 
Result so far: 7289.7619
Subtracting 189 from 190 leaves us with 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Step 11:
The number 21 fits into 10 0 times, leaving a remainder of 10.
Write down 0 as next digit of the result. 
Result so far: 7289.7619
Deduct 0 from 10 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.

On to step 12:
If we divide 100 by 21, we get 4 and a remainder of 16.
Put 4 as the next digit of the answer. 
Result so far: 7289.761904
Subtract 84 from 100 to get 16.
Since there are no more digits in the dividend, we add a zero to the remainder making it 160, and continue the process.

Step 13:
The number 21 fits into 160 7 times, leaving a remainder of 13.
Write down 7 as next digit of the result. 
Result so far: 7289.7619047
If we subtract 147 from 160, we get 13.
Since there are no more digits in the dividend, we add a zero to the remainder making it 130, and continue the process.

Advancing to step 14:
21 can be fit into 130 6 times, resulting in a remainder of 4.
The next digit of our result is 6. 
Result so far: 7289.76190476
Deduct 126 from 130 and we're left with 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

After the division, we end up with 7289.76190476 and a remainder of 4e-09.