217353 ÷ 21 
Let's see how many times 21 fits into 217353.

Advancing to step 1:
21 goes into 2 0 times with a remainder of 2.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Deduct 0 from 2 and we're left with 2.
Bring next digit (1) of the dividend behind the 2 and repeat the process: 21 / 21

On to step 2:
The number 21 fits into 21 1 times, leaving a remainder of 0.
The next digit of our result is 1. 
Result so far: 1.0
The remainder is 0 after subtracting 21 from 21.
Bring next digit (7) of the dividend behind the 0 and repeat the process: 7 / 21

Moving on to step 3:
If we divide 7 by 21, we get 0 and a remainder of 7.
Use 0 as the next digit of our solution. 
Result so far: 10.0
Subtract 0 from 7 to get 7.
Fetch the next digit (3) from the dividend, attach it to 7 and continue: 73 / 21

Advancing to step 4:
When dividing 73 by 21, we get 3 with a remainder of 10.
Record the quotient 3 as the next digit in the result. 
Result so far: 103.0
Subtracting 63 from 73 leaves us with 10.
Take the next digit (5) from the dividend and append it to 10, then repeat: 105 / 21

On to step 5:
The number 21 fits into 105 5 times, leaving a remainder of 0.
Record the quotient 5 as the next digit in the result. 
Result so far: 1035.0
If we take 105 away from 105, we end up with 0.
Bring next digit (3) of the dividend behind the 0 and repeat the process: 3 / 21

Let's proceed to step 6:
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: 10350.0
The remainder is 3 after subtracting 0 from 3.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

Advancing to step 7:
If we divide 30 by 21, we get 1 and a remainder of 9.
The next digit of our result is 1. 
Result so far: 10350.1
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.

Let's proceed to step 8:
If we divide 90 by 21, we get 4 and a remainder of 6.
Write down 4 as next digit of the result. 
Result so far: 10350.14
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.

Advancing to step 9:
The number 21 fits into 60 2 times, leaving a remainder of 18.
The next digit of our result is 2. 
Result so far: 10350.142
If we take 42 away from 60, we end up 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.

Moving on to step 10:
21 goes into 180 8 times with a remainder of 12.
The number 8 becomes the next digit in our result. 
Result so far: 10350.1428
The remainder is 12 after subtracting 168 from 180.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

Going ahead to step 11:
120 divided by 21 is 5 with a remainder of 15.
Record the quotient 5 as the next digit in the result. 
Result so far: 10350.14285
If we take 105 away from 120, we end up with 15.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

Advancing to step 12:
150 divided by 21 is 7 with a remainder of 3.
The number 7 becomes the next digit in our result. 
Result so far: 10350.142857
If we take 147 away from 150, we end up 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.

Advancing to step 13:
21 goes into 30 1 times with a remainder of 9.
Use 1 as the next digit of our solution. 
Result so far: 10350.1428571
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.

On to step 14:
The number 21 fits into 90 4 times, leaving a remainder of 6.
The next digit of our result is 4. 
Result so far: 10350.14285714
Deduct 84 from 90 and we're left 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 10350.14285714, with a leftover of 6e-09.