300397 divided by 21 
We want to figure out the number of times 300397 can be divided by 21.

Advancing to step 1:
21 can be fit into 3 0 times, resulting in a remainder of 3.
The next digit of our result is 0. 
Result so far: 0.0
If we take 0 away from 3, we end up with 3.
Take the next digit (0) from the dividend and append it to 3, then repeat: 30 / 21

Going ahead to step 2:
If we divide 30 by 21, we get 1 and a remainder of 9.
Record the quotient 1 as the next digit in the result. 
Result so far: 1.0
If we take 21 away from 30, we end up with 9.
Include the next digit (0) from the dividend after 9, then repeat: 90 / 21

Going ahead to step 3:
90 divided by 21 is 4 with a remainder of 6.
The next digit of our result is 4. 
Result so far: 14.0
Deduct 84 from 90 and we're left with 6.
Bring next digit (3) of the dividend behind the 6 and repeat the process: 63 / 21

Step 4:
21 goes into 63 3 times with a remainder of 0.
Write down 3 as next digit of the result. 
Result so far: 143.0
If we subtract 63 from 63, we get 0.
Take the next digit (9) from the dividend and append it to 0, then repeat: 9 / 21

Going ahead to step 5:
The number 21 fits into 9 0 times, leaving a remainder of 9.
Use 0 as the next digit of our solution. 
Result so far: 1430.0
Subtracting 0 from 9 leaves us with 9.
Grab the next digit (7) from the dividend, add it to 9, then carry on: 97 / 21

Advancing to step 6:
If we divide 97 by 21, we get 4 and a remainder of 13.
Put 4 as the next digit of the answer. 
Result so far: 14304.0
Deduct 84 from 97 and we're left 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.

Moving on to step 7:
130 divided by 21 is 6 with a remainder of 4.
Use 6 as the next digit of our solution. 
Result so far: 14304.6
If we subtract 126 from 130, we get 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

On to step 8:
When dividing 40 by 21, we get 1 with a remainder of 19.
The next digit of our result is 1. 
Result so far: 14304.61
The remainder is 19 after subtracting 21 from 40.
Since there are no more digits in the dividend, we add a zero to the remainder making it 190, and continue the process.

Let's proceed to step 9:
The number 21 fits into 190 9 times, leaving a remainder of 1.
The next digit of our result is 9. 
Result so far: 14304.619
If we subtract 189 from 190, we get 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Moving on to step 10:
If we divide 10 by 21, we get 0 and a remainder of 10.
Write down 0 as next digit of the result. 
Result so far: 14304.619
Subtract 0 from 10 to get 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Advancing to step 11:
21 can be fit into 100 4 times, resulting in a remainder of 16.
Record the quotient 4 as the next digit in the result. 
Result so far: 14304.61904
Deduct 84 from 100 and we're left with 16.
Since there are no more digits in the dividend, we add a zero to the remainder making it 160, and continue the process.

Advancing to step 12:
160 divided by 21 is 7 with a remainder of 13.
Record the quotient 7 as the next digit in the result. 
Result so far: 14304.619047
Subtract 147 from 160 to 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 13:
21 goes into 130 6 times with a remainder of 4.
Put 6 as the next digit of the answer. 
Result so far: 14304.6190476
Subtracting 126 from 130 leaves us 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.

Advancing to step 14:
The number 21 fits into 40 1 times, leaving a remainder of 19.
Use 1 as the next digit of our solution. 
Result so far: 14304.61904761
The remainder is 19 after subtracting 21 from 40.
Since there are no more digits in the dividend, we add a zero to the remainder making it 190, and continue the process.

The final outcome is 14304.61904761, with a leftover of 1.9e-08.