521421 ÷ 81 
We want to divide 521421 by 81.

Step 1:
5 divided by 81 is 0 with a remainder of 5.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
If we take 0 away from 5, we end up with 5.
Append the next digit (2) from the dividend to 5 and continue with: 52 / 81

Moving on to step 2:
81 can be fit into 52 0 times, resulting in a remainder of 52.
The next digit of our result is 0. 
Result so far: 0.0
Subtract 0 from 52 to get 52.
Append the next digit (1) from the dividend to 52 and continue with: 521 / 81

Moving on to step 3:
The number 81 fits into 521 6 times, leaving a remainder of 35.
Record the quotient 6 as the next digit in the result. 
Result so far: 6.0
Subtracting 486 from 521 leaves us with 35.
Fetch the next digit (4) from the dividend, attach it to 35 and continue: 354 / 81

Moving on to step 4:
If we divide 354 by 81, we get 4 and a remainder of 30.
The next digit of our result is 4. 
Result so far: 64.0
Deduct 324 from 354 and we're left with 30.
Bring next digit (2) of the dividend behind the 30 and repeat the process: 302 / 81

Moving on to step 5:
81 goes into 302 3 times with a remainder of 59.
Use 3 as the next digit of our solution. 
Result so far: 643.0
If we take 243 away from 302, we end up with 59.
Bring next digit (1) of the dividend behind the 59 and repeat the process: 591 / 81

Going ahead to step 6:
81 goes into 591 7 times with a remainder of 24.
Write down 7 as next digit of the result. 
Result so far: 6437.0
If we subtract 567 from 591, we get 24.
Since there are no more digits in the dividend, we add a zero to the remainder making it 240, and continue the process.

Moving on to step 7:
81 can be fit into 240 2 times, resulting in a remainder of 78.
Record the quotient 2 as the next digit in the result. 
Result so far: 6437.2
The remainder is 78 after subtracting 162 from 240.
Since there are no more digits in the dividend, we add a zero to the remainder making it 780, and continue the process.

Step 8:
81 can be fit into 780 9 times, resulting in a remainder of 51.
The number 9 becomes the next digit in our result. 
Result so far: 6437.29
Subtract 729 from 780 to get 51.
Since there are no more digits in the dividend, we add a zero to the remainder making it 510, and continue the process.

Let's proceed to step 9:
510 divided by 81 is 6 with a remainder of 24.
Use 6 as the next digit of our solution. 
Result so far: 6437.296
The remainder is 24 after subtracting 486 from 510.
Since there are no more digits in the dividend, we add a zero to the remainder making it 240, and continue the process.

Advancing to step 10:
If we divide 240 by 81, we get 2 and a remainder of 78.
The number 2 becomes the next digit in our result. 
Result so far: 6437.2962
Deduct 162 from 240 and we're left with 78.
Since there are no more digits in the dividend, we add a zero to the remainder making it 780, and continue the process.

Advancing to step 11:
When dividing 780 by 81, we get 9 with a remainder of 51.
The next digit of our result is 9. 
Result so far: 6437.29629
The remainder is 51 after subtracting 729 from 780.
Since there are no more digits in the dividend, we add a zero to the remainder making it 510, and continue the process.

On to step 12:
When dividing 510 by 81, we get 6 with a remainder of 24.
Use 6 as the next digit of our solution. 
Result so far: 6437.296296
Subtract 486 from 510 to get 24.
Since there are no more digits in the dividend, we add a zero to the remainder making it 240, and continue the process.

Advancing to step 13:
When dividing 240 by 81, we get 2 with a remainder of 78.
Put 2 as the next digit of the answer. 
Result so far: 6437.2962962
Subtract 162 from 240 to get 78.
Since there are no more digits in the dividend, we add a zero to the remainder making it 780, and continue the process.

Step 14:
If we divide 780 by 81, we get 9 and a remainder of 51.
Write down 9 as next digit of the result. 
Result so far: 6437.29629629
Subtract 729 from 780 to get 51.
Since there are no more digits in the dividend, we add a zero to the remainder making it 510, and continue the process.

In conclusion, the division gives 6437.29629629 with a balance of 5.1e-08.