We divide 542123 by 21
Let's see how many times 21 fits into 542123.

Let's proceed to step 1:
When dividing 5 by 21, we get 0 with a remainder of 5.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Subtract 0 from 5 to get 5.
Fetch the next digit (4) from the dividend, attach it to 5 and continue: 54 / 21

Let's proceed to step 2:
When dividing 54 by 21, we get 2 with a remainder of 12.
The next digit of our result is 2. 
Result so far: 2.0
Subtract 42 from 54 to get 12.
Grab the next digit (2) from the dividend, add it to 12, then carry on: 122 / 21

Going ahead to step 3:
21 can be fit into 122 5 times, resulting in a remainder of 17.
Use 5 as the next digit of our solution. 
Result so far: 25.0
If we subtract 105 from 122, we get 17.
Grab the next digit (1) from the dividend, add it to 17, then carry on: 171 / 21

Advancing to step 4:
21 can be fit into 171 8 times, resulting in a remainder of 3.
Write down 8 as next digit of the result. 
Result so far: 258.0
If we subtract 168 from 171, we get 3.
Bring next digit (2) of the dividend behind the 3 and repeat the process: 32 / 21

Advancing to step 5:
21 goes into 32 1 times with a remainder of 11.
Record the quotient 1 as the next digit in the result. 
Result so far: 2581.0
If we subtract 21 from 32, we get 11.
Append the next digit (3) from the dividend to 11 and continue with: 113 / 21

Going ahead to step 6:
If we divide 113 by 21, we get 5 and a remainder of 8.
The number 5 becomes the next digit in our result. 
Result so far: 25815.0
Subtract 105 from 113 to get 8.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

Step 7:
21 can be fit into 80 3 times, resulting in a remainder of 17.
Write down 3 as next digit of the result. 
Result so far: 25815.3
If we take 63 away from 80, we end up with 17.
Since there are no more digits in the dividend, we add a zero to the remainder making it 170, and continue the process.

Let's proceed to step 8:
If we divide 170 by 21, we get 8 and a remainder of 2.
Write down 8 as next digit of the result. 
Result so far: 25815.38
The remainder is 2 after subtracting 168 from 170.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

Going ahead to step 9:
If we divide 20 by 21, we get 0 and a remainder of 20.
Use 0 as the next digit of our solution. 
Result so far: 25815.38
If we take 0 away from 20, we end up with 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

Going ahead to step 10:
The number 21 fits into 200 9 times, leaving a remainder of 11.
Write down 9 as next digit of the result. 
Result so far: 25815.3809
If we take 189 away from 200, we end up with 11.
Since there are no more digits in the dividend, we add a zero to the remainder making it 110, and continue the process.

Advancing to step 11:
When dividing 110 by 21, we get 5 with a remainder of 5.
The number 5 becomes the next digit in our result. 
Result so far: 25815.38095
The remainder is 5 after subtracting 105 from 110.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

Step 12:
When dividing 50 by 21, we get 2 with a remainder of 8.
The number 2 becomes the next digit in our result. 
Result so far: 25815.380952
Subtracting 42 from 50 leaves us with 8.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

On to step 13:
80 divided by 21 is 3 with a remainder of 17.
The next digit of our result is 3. 
Result so far: 25815.3809523
Subtract 63 from 80 to get 17.
Since there are no more digits in the dividend, we add a zero to the remainder making it 170, and continue the process.

On to step 14:
170 divided by 21 is 8 with a remainder of 2.
Use 8 as the next digit of our solution. 
Result so far: 25815.38095238
The remainder is 2 after subtracting 168 from 170.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

The final result is 25815.38095238 with a remainder of 2e-09.