753355 divided by 21 
We want to figure out the number of times 753355 can be divided by 21.

Step 1:
7 divided by 21 is 0 with a remainder of 7.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtract 0 from 7 to get 7.
Grab the next digit (5) from the dividend, add it to 7, then carry on: 75 / 21

On to step 2:
When dividing 75 by 21, we get 3 with a remainder of 12.
The next digit of our result is 3. 
Result so far: 3.0
If we take 63 away from 75, we end up with 12.
Bring next digit (3) of the dividend behind the 12 and repeat the process: 123 / 21

Moving on to step 3:
The number 21 fits into 123 5 times, leaving a remainder of 18.
Write down 5 as next digit of the result. 
Result so far: 35.0
Subtract 105 from 123 to get 18.
Grab the next digit (3) from the dividend, add it to 18, then carry on: 183 / 21

On to step 4:
When dividing 183 by 21, we get 8 with a remainder of 15.
Put 8 as the next digit of the answer. 
Result so far: 358.0
Subtracting 168 from 183 leaves us with 15.
Bring next digit (5) of the dividend behind the 15 and repeat the process: 155 / 21

Moving on to step 5:
21 can be fit into 155 7 times, resulting in a remainder of 8.
The number 7 becomes the next digit in our result. 
Result so far: 3587.0
If we take 147 away from 155, we end up with 8.
Include the next digit (5) from the dividend after 8, then repeat: 85 / 21

Going ahead to step 6:
21 can be fit into 85 4 times, resulting in a remainder of 1.
Write down 4 as next digit of the result. 
Result so far: 35874.0
The remainder is 1 after subtracting 84 from 85.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Advancing to step 7:
21 can be fit into 10 0 times, resulting in a remainder of 10.
Use 0 as the next digit of our solution. 
Result so far: 35874.0
Subtracting 0 from 10 leaves us 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.

Going ahead to step 8:
21 goes into 100 4 times with a remainder of 16.
Put 4 as the next digit of the answer. 
Result so far: 35874.04
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.

Let's proceed to step 9:
21 goes into 160 7 times with a remainder of 13.
Put 7 as the next digit of the answer. 
Result so far: 35874.047
Deduct 147 from 160 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.

Let's proceed to step 10:
21 goes into 130 6 times with a remainder of 4.
Use 6 as the next digit of our solution. 
Result so far: 35874.0476
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.

Step 11:
21 goes into 40 1 times with a remainder of 19.
Write down 1 as next digit of the result. 
Result so far: 35874.04761
If we subtract 21 from 40, we 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.

Let's proceed to step 12:
The number 21 fits into 190 9 times, leaving a remainder of 1.
The number 9 becomes the next digit in our result. 
Result so far: 35874.047619
Subtract 189 from 190 to 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.

Let's proceed to step 13:
21 can be fit into 10 0 times, resulting in a remainder of 10.
Record the quotient 0 as the next digit in the result. 
Result so far: 35874.047619
If we subtract 0 from 10, we 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.

Going ahead to step 14:
The number 21 fits into 100 4 times, leaving a remainder of 16.
Use 4 as the next digit of our solution. 
Result so far: 35874.04761904
Subtract 84 from 100 to 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.

After the division, we end up with 35874.04761904 and a remainder of 1.6e-08.