Let's divide 21213287 by 407
We're looking to find how many times 407 goes into 21213287.

Advancing to step 1:
The number 407 fits into 2 0 times, leaving a remainder of 2.
Write down 0 as next digit of the result. 
Result so far: 0.0
Deduct 0 from 2 and we're left with 2.
Take the next digit (1) from the dividend and append it to 2, then repeat: 21 / 407

Moving on to step 2:
If we divide 21 by 407, we get 0 and a remainder of 21.
Write down 0 as next digit of the result. 
Result so far: 0.0
If we subtract 0 from 21, we get 21.
Grab the next digit (2) from the dividend, add it to 21, then carry on: 212 / 407

Going ahead to step 3:
When dividing 212 by 407, we get 0 with a remainder of 212.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
If we take 0 away from 212, we end up with 212.
Append the next digit (1) from the dividend to 212 and continue with: 2121 / 407

Advancing to step 4:
407 goes into 2121 5 times with a remainder of 86.
The next digit of our result is 5. 
Result so far: 5.0
If we take 2035 away from 2121, we end up with 86.
Bring next digit (3) of the dividend behind the 86 and repeat the process: 863 / 407

Step 5:
407 can be fit into 863 2 times, resulting in a remainder of 49.
Use 2 as the next digit of our solution. 
Result so far: 52.0
If we take 814 away from 863, we end up with 49.
Take the next digit (2) from the dividend and append it to 49, then repeat: 492 / 407

Going ahead to step 6:
407 can be fit into 492 1 times, resulting in a remainder of 85.
Record the quotient 1 as the next digit in the result. 
Result so far: 521.0
Deduct 407 from 492 and we're left with 85.
Fetch the next digit (8) from the dividend, attach it to 85 and continue: 858 / 407

Going ahead to step 7:
407 can be fit into 858 2 times, resulting in a remainder of 44.
Use 2 as the next digit of our solution. 
Result so far: 5212.0
The remainder is 44 after subtracting 814 from 858.
Take the next digit (7) from the dividend and append it to 44, then repeat: 447 / 407

On to step 8:
When dividing 447 by 407, we get 1 with a remainder of 40.
Put 1 as the next digit of the answer. 
Result so far: 52121.0
If we subtract 407 from 447, we get 40.
Since there are no more digits in the dividend, we add a zero to the remainder making it 400, and continue the process.

Let's proceed to step 9:
407 can be fit into 400 0 times, resulting in a remainder of 400.
The number 0 becomes the next digit in our result. 
Result so far: 52121.0
If we subtract 0 from 400, we get 400.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4000, and continue the process.

Moving on to step 10:
The number 407 fits into 4000 9 times, leaving a remainder of 337.
Use 9 as the next digit of our solution. 
Result so far: 52121.09
Subtract 3663 from 4000 to get 337.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3370, and continue the process.

Let's proceed to step 11:
When dividing 3370 by 407, we get 8 with a remainder of 114.
The next digit of our result is 8. 
Result so far: 52121.098
If we subtract 3256 from 3370, we get 114.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1140, and continue the process.

Advancing to step 12:
When dividing 1140 by 407, we get 2 with a remainder of 326.
The number 2 becomes the next digit in our result. 
Result so far: 52121.0982
Subtract 814 from 1140 to get 326.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3260, and continue the process.

Step 13:
If we divide 3260 by 407, we get 8 and a remainder of 4.
Record the quotient 8 as the next digit in the result. 
Result so far: 52121.09828
If we subtract 3256 from 3260, 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.

Going ahead to step 14:
When dividing 40 by 407, we get 0 with a remainder of 40.
Record the quotient 0 as the next digit in the result. 
Result so far: 52121.09828
If we subtract 0 from 40, we get 40.
Since there are no more digits in the dividend, we add a zero to the remainder making it 400, and continue the process.

Advancing to step 15:
407 can be fit into 400 0 times, resulting in a remainder of 400.
Record the quotient 0 as the next digit in the result. 
Result so far: 52121.09828
Subtract 0 from 400 to get 400.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4000, and continue the process.

In conclusion, the division gives 52121.09828 with a balance of 4e-06.