Let's divide 305129 by 21
We're looking to find how many times 21 goes into 305129.

Step 1:
When dividing 3 by 21, we get 0 with a remainder of 3.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtract 0 from 3 to get 3.
Include the next digit (0) from the dividend after 3, then repeat: 30 / 21

Moving on to step 2:
21 can be fit into 30 1 times, resulting in a remainder of 9.
Record the quotient 1 as the next digit in the result. 
Result so far: 1.0
If we subtract 21 from 30, we get 9.
Include the next digit (5) from the dividend after 9, then repeat: 95 / 21

Going ahead to step 3:
95 divided by 21 is 4 with a remainder of 11.
Put 4 as the next digit of the answer. 
Result so far: 14.0
Subtracting 84 from 95 leaves us with 11.
Take the next digit (1) from the dividend and append it to 11, then repeat: 111 / 21

Going ahead to step 4:
If we divide 111 by 21, we get 5 and a remainder of 6.
Record the quotient 5 as the next digit in the result. 
Result so far: 145.0
Deduct 105 from 111 and we're left with 6.
Include the next digit (2) from the dividend after 6, then repeat: 62 / 21

Let's proceed to step 5:
If we divide 62 by 21, we get 2 and a remainder of 20.
The number 2 becomes the next digit in our result. 
Result so far: 1452.0
The remainder is 20 after subtracting 42 from 62.
Append the next digit (9) from the dividend to 20 and continue with: 209 / 21

On to step 6:
21 can be fit into 209 9 times, resulting in a remainder of 20.
Use 9 as the next digit of our solution. 
Result so far: 14529.0
If we subtract 189 from 209, 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.

Going ahead to step 7:
200 divided by 21 is 9 with a remainder of 11.
Write down 9 as next digit of the result. 
Result so far: 14529.9
If we take 189 away from 200, we end up with 11.
Since there are no more digits in the dividend, we add a zero to the remainder making it 110, and continue the process.

Let's proceed to step 8:
When dividing 110 by 21, we get 5 with a remainder of 5.
Write down 5 as next digit of the result. 
Result so far: 14529.95
The remainder is 5 after subtracting 105 from 110.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

Going ahead to step 9:
21 goes into 50 2 times with a remainder of 8.
The next digit of our result is 2. 
Result so far: 14529.952
Subtracting 42 from 50 leaves us with 8.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

Step 10:
80 divided by 21 is 3 with a remainder of 17.
The next digit of our result is 3. 
Result so far: 14529.9523
Subtract 63 from 80 to get 17.
Since there are no more digits in the dividend, we add a zero to the remainder making it 170, and continue the process.

Going ahead to step 11:
The number 21 fits into 170 8 times, leaving a remainder of 2.
Use 8 as the next digit of our solution. 
Result so far: 14529.95238
Subtracting 168 from 170 leaves us with 2.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

Advancing to step 12:
When dividing 20 by 21, we get 0 with a remainder of 20.
Write down 0 as next digit of the result. 
Result so far: 14529.95238
The remainder is 20 after subtracting 0 from 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

Moving on to step 13:
If we divide 200 by 21, we get 9 and a remainder of 11.
Record the quotient 9 as the next digit in the result. 
Result so far: 14529.9523809
The remainder is 11 after subtracting 189 from 200.
Since there are no more digits in the dividend, we add a zero to the remainder making it 110, and continue the process.

Going ahead to step 14:
21 can be fit into 110 5 times, resulting in a remainder of 5.
Record the quotient 5 as the next digit in the result. 
Result so far: 14529.95238095
The remainder is 5 after subtracting 105 from 110.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

After the division, we end up with 14529.95238095 and a remainder of 5e-09.