We look at the division of 340266 by 21 
We want to figure out the number of times 340266 can be divided by 21.

On to step 1:
21 goes into 3 0 times with a remainder of 3.
Write down 0 as next digit of the result. 
Result so far: 0.0
Subtracting 0 from 3 leaves us with 3.
Include the next digit (4) from the dividend after 3, then repeat: 34 / 21

Let's proceed to step 2:
If we divide 34 by 21, we get 1 and a remainder of 13.
Put 1 as the next digit of the answer. 
Result so far: 1.0
The remainder is 13 after subtracting 21 from 34.
Include the next digit (0) from the dividend after 13, then repeat: 130 / 21

Going ahead to step 3:
The number 21 fits into 130 6 times, leaving a remainder of 4.
The next digit of our result is 6. 
Result so far: 16.0
If we subtract 126 from 130, we get 4.
Bring next digit (2) of the dividend behind the 4 and repeat the process: 42 / 21

Step 4:
When dividing 42 by 21, we get 2 with a remainder of 0.
Write down 2 as next digit of the result. 
Result so far: 162.0
If we subtract 42 from 42, we get 0.
Include the next digit (6) from the dividend after 0, then repeat: 6 / 21

On to step 5:
When dividing 6 by 21, we get 0 with a remainder of 6.
The next digit of our result is 0. 
Result so far: 1620.0
If we subtract 0 from 6, we get 6.
Bring next digit (6) of the dividend behind the 6 and repeat the process: 66 / 21

Moving on to step 6:
If we divide 66 by 21, we get 3 and a remainder of 3.
Record the quotient 3 as the next digit in the result. 
Result so far: 16203.0
Subtracting 63 from 66 leaves us with 3.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

Step 7:
The number 21 fits into 30 1 times, leaving a remainder of 9.
Use 1 as the next digit of our solution. 
Result so far: 16203.1
If we subtract 21 from 30, we get 9.
Since there are no more digits in the dividend, we add a zero to the remainder making it 90, and continue the process.

On to step 8:
90 divided by 21 is 4 with a remainder of 6.
Write down 4 as next digit of the result. 
Result so far: 16203.14
The remainder is 6 after subtracting 84 from 90.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

Advancing to step 9:
60 divided by 21 is 2 with a remainder of 18.
Use 2 as the next digit of our solution. 
Result so far: 16203.142
Deduct 42 from 60 and we're left with 18.
Since there are no more digits in the dividend, we add a zero to the remainder making it 180, and continue the process.

Let's proceed to step 10:
180 divided by 21 is 8 with a remainder of 12.
The number 8 becomes the next digit in our result. 
Result so far: 16203.1428
If we subtract 168 from 180, we get 12.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

On to step 11:
21 goes into 120 5 times with a remainder of 15.
The next digit of our result is 5. 
Result so far: 16203.14285
If we subtract 105 from 120, we get 15.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

Going ahead to step 12:
When dividing 150 by 21, we get 7 with a remainder of 3.
Write down 7 as next digit of the result. 
Result so far: 16203.142857
Subtracting 147 from 150 leaves us with 3.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

Going ahead to step 13:
30 divided by 21 is 1 with a remainder of 9.
The next digit of our result is 1. 
Result so far: 16203.1428571
Deduct 21 from 30 and we're left with 9.
Since there are no more digits in the dividend, we add a zero to the remainder making it 90, and continue the process.

Let's proceed to step 14:
21 goes into 90 4 times with a remainder of 6.
The next digit of our result is 4. 
Result so far: 16203.14285714
If we take 84 away from 90, we end up with 6.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

The final outcome is 16203.14285714, with a leftover of 6e-09.