Let's divide 543985 by 21
Let's see how many times 21 fits into 543985.

Going ahead to step 1:
21 can be fit into 5 0 times, resulting in a remainder of 5.
The next digit of our result is 0. 
Result so far: 0.0
Subtracting 0 from 5 leaves us with 5.
Grab the next digit (4) from the dividend, add it to 5, then carry on: 54 / 21

On to step 2:
54 divided by 21 is 2 with a remainder of 12.
Use 2 as the next digit of our solution. 
Result so far: 2.0
The remainder is 12 after subtracting 42 from 54.
Bring next digit (3) of the dividend behind the 12 and repeat the process: 123 / 21

Moving on to step 3:
21 can be fit into 123 5 times, resulting in a remainder of 18.
Put 5 as the next digit of the answer. 
Result so far: 25.0
Subtract 105 from 123 to get 18.
Bring next digit (9) of the dividend behind the 18 and repeat the process: 189 / 21

Let's proceed to step 4:
When dividing 189 by 21, we get 9 with a remainder of 0.
Put 9 as the next digit of the answer. 
Result so far: 259.0
If we subtract 189 from 189, we get 0.
Include the next digit (8) from the dividend after 0, then repeat: 8 / 21

Let's proceed to step 5:
When dividing 8 by 21, we get 0 with a remainder of 8.
The number 0 becomes the next digit in our result. 
Result so far: 2590.0
If we subtract 0 from 8, we get 8.
Include the next digit (5) from the dividend after 8, then repeat: 85 / 21

Advancing to step 6:
85 divided by 21 is 4 with a remainder of 1.
Use 4 as the next digit of our solution. 
Result so far: 25904.0
If we subtract 84 from 85, 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.

Advancing to step 7:
The number 21 fits into 10 0 times, leaving a remainder of 10.
Write down 0 as next digit of the result. 
Result so far: 25904.0
Subtract 0 from 10 to 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.

Let's proceed to step 8:
If we divide 100 by 21, we get 4 and a remainder of 16.
The number 4 becomes the next digit in our result. 
Result so far: 25904.04
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.

Going ahead to step 9:
21 can be fit into 160 7 times, resulting in a remainder of 13.
The number 7 becomes the next digit in our result. 
Result so far: 25904.047
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:
The number 21 fits into 130 6 times, leaving a remainder of 4.
Write down 6 as next digit of the result. 
Result so far: 25904.0476
If we subtract 126 from 130, 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.

On to step 11:
If we divide 40 by 21, we get 1 and a remainder of 19.
The next digit of our result is 1. 
Result so far: 25904.04761
If we take 21 away from 40, we end up with 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:
If we divide 190 by 21, we get 9 and a remainder of 1.
Use 9 as the next digit of our solution. 
Result so far: 25904.047619
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.

Moving on to step 13:
10 divided by 21 is 0 with a remainder of 10.
Put 0 as the next digit of the answer. 
Result so far: 25904.047619
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.

Moving on to step 14:
100 divided by 21 is 4 with a remainder of 16.
The next digit of our result is 4. 
Result so far: 25904.04761904
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.

The final result is 25904.04761904 with a remainder of 1.6e-08.