Let's divide 345308 by 21
Let's see how many times 21 fits into 345308.

On to step 1:
If we divide 3 by 21, we get 0 and a remainder of 3.
Write down 0 as next digit of the result. 
Result so far: 0.0
Subtract 0 from 3 to get 3.
Append the next digit (4) from the dividend to 3 and continue with: 34 / 21

Let's proceed to step 2:
The number 21 fits into 34 1 times, leaving a remainder of 13.
Use 1 as the next digit of our solution. 
Result so far: 1.0
Subtracting 21 from 34 leaves us with 13.
Fetch the next digit (5) from the dividend, attach it to 13 and continue: 135 / 21

Step 3:
21 goes into 135 6 times with a remainder of 9.
Write down 6 as next digit of the result. 
Result so far: 16.0
If we take 126 away from 135, we end up with 9.
Bring next digit (3) of the dividend behind the 9 and repeat the process: 93 / 21

Step 4:
If we divide 93 by 21, we get 4 and a remainder of 9.
Write down 4 as next digit of the result. 
Result so far: 164.0
The remainder is 9 after subtracting 84 from 93.
Grab the next digit (0) from the dividend, add it to 9, then carry on: 90 / 21

Let's proceed to step 5:
If we divide 90 by 21, we get 4 and a remainder of 6.
The number 4 becomes the next digit in our result. 
Result so far: 1644.0
If we subtract 84 from 90, we get 6.
Bring next digit (8) of the dividend behind the 6 and repeat the process: 68 / 21

On to step 6:
If we divide 68 by 21, we get 3 and a remainder of 5.
Put 3 as the next digit of the answer. 
Result so far: 16443.0
Subtract 63 from 68 to get 5.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

On to step 7:
The number 21 fits into 50 2 times, leaving a remainder of 8.
Put 2 as the next digit of the answer. 
Result so far: 16443.2
Deduct 42 from 50 and we're left 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.

Moving on to step 8:
The number 21 fits into 80 3 times, leaving a remainder of 17.
The number 3 becomes the next digit in our result. 
Result so far: 16443.23
Subtracting 63 from 80 leaves us with 17.
Since there are no more digits in the dividend, we add a zero to the remainder making it 170, and continue the process.

Step 9:
21 can be fit into 170 8 times, resulting in a remainder of 2.
Record the quotient 8 as the next digit in the result. 
Result so far: 16443.238
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 10:
20 divided by 21 is 0 with a remainder of 20.
The number 0 becomes the next digit in our result. 
Result so far: 16443.238
If we take 0 away from 20, we end up 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 11:
200 divided by 21 is 9 with a remainder of 11.
Write down 9 as next digit of the result. 
Result so far: 16443.23809
If we subtract 189 from 200, we get 11.
Since there are no more digits in the dividend, we add a zero to the remainder making it 110, and continue the process.

Advancing to step 12:
The number 21 fits into 110 5 times, leaving a remainder of 5.
Write down 5 as next digit of the result. 
Result so far: 16443.238095
If we subtract 105 from 110, we get 5.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

Advancing to step 13:
21 goes into 50 2 times with a remainder of 8.
Put 2 as the next digit of the answer. 
Result so far: 16443.2380952
The remainder is 8 after subtracting 42 from 50.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

Moving on to step 14:
When dividing 80 by 21, we get 3 with a remainder of 17.
Record the quotient 3 as the next digit in the result. 
Result so far: 16443.23809523
If we subtract 63 from 80, we 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.

After the division, we end up with 16443.23809523 and a remainder of 1.7e-08.