Let's divide 352507 by 21
We're looking to find how many times 21 goes into 352507.

Step 1:
The number 21 fits into 3 0 times, leaving a remainder of 3.
The next digit of our result is 0. 
Result so far: 0.0
Subtracting 0 from 3 leaves us with 3.
Fetch the next digit (5) from the dividend, attach it to 3 and continue: 35 / 21

Going ahead to step 2:
If we divide 35 by 21, we get 1 and a remainder of 14.
Put 1 as the next digit of the answer. 
Result so far: 1.0
Subtracting 21 from 35 leaves us with 14.
Take the next digit (2) from the dividend and append it to 14, then repeat: 142 / 21

Going ahead to step 3:
When dividing 142 by 21, we get 6 with a remainder of 16.
Write down 6 as next digit of the result. 
Result so far: 16.0
Subtract 126 from 142 to get 16.
Include the next digit (5) from the dividend after 16, then repeat: 165 / 21

Going ahead to step 4:
165 divided by 21 is 7 with a remainder of 18.
Write down 7 as next digit of the result. 
Result so far: 167.0
Deduct 147 from 165 and we're left with 18.
Include the next digit (0) from the dividend after 18, then repeat: 180 / 21

Let's proceed to step 5:
21 goes into 180 8 times with a remainder of 12.
Record the quotient 8 as the next digit in the result. 
Result so far: 1678.0
Subtracting 168 from 180 leaves us with 12.
Bring next digit (7) of the dividend behind the 12 and repeat the process: 127 / 21

On to step 6:
The number 21 fits into 127 6 times, leaving a remainder of 1.
Use 6 as the next digit of our solution. 
Result so far: 16786.0
If we subtract 126 from 127, 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 7:
10 divided by 21 is 0 with a remainder of 10.
The number 0 becomes the next digit in our result. 
Result so far: 16786.0
If we take 0 away from 10, we end up with 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Let's proceed to step 8:
If we divide 100 by 21, we get 4 and a remainder of 16.
Write down 4 as next digit of the result. 
Result so far: 16786.04
If we subtract 84 from 100, we get 16.
Since there are no more digits in the dividend, we add a zero to the remainder making it 160, and continue the process.

Going ahead to step 9:
21 can be fit into 160 7 times, resulting in a remainder of 13.
Record the quotient 7 as the next digit in the result. 
Result so far: 16786.047
If we subtract 147 from 160, we 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.

Moving on to step 10:
21 can be fit into 130 6 times, resulting in a remainder of 4.
The number 6 becomes the next digit in our result. 
Result so far: 16786.0476
Deduct 126 from 130 and we're left 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.

Moving on to step 11:
21 goes into 40 1 times with a remainder of 19.
Use 1 as the next digit of our solution. 
Result so far: 16786.04761
Subtract 21 from 40 to get 19.
Since there are no more digits in the dividend, we add a zero to the remainder making it 190, and continue the process.

Moving on to step 12:
When dividing 190 by 21, we get 9 with a remainder of 1.
Record the quotient 9 as the next digit in the result. 
Result so far: 16786.047619
The remainder is 1 after subtracting 189 from 190.
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 13:
21 can be fit into 10 0 times, resulting in a remainder of 10.
Write down 0 as next digit of the result. 
Result so far: 16786.047619
If we take 0 away from 10, we end up with 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Moving on to step 14:
The number 21 fits into 100 4 times, leaving a remainder of 16.
The next digit of our result is 4. 
Result so far: 16786.04761904
If we take 84 away from 100, we end up 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.

In conclusion, the division gives 16786.04761904 with a balance of 1.6e-08.