We're dividing 121234 by 21 
Our goal is to divide 121234 by 21.

Step 1:
If we divide 1 by 21, we get 0 and a remainder of 1.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
The remainder is 1 after subtracting 0 from 1.
Include the next digit (2) from the dividend after 1, then repeat: 12 / 21

Step 2:
21 goes into 12 0 times with a remainder of 12.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
The remainder is 12 after subtracting 0 from 12.
Take the next digit (1) from the dividend and append it to 12, then repeat: 121 / 21

Moving on to step 3:
If we divide 121 by 21, we get 5 and a remainder of 16.
Use 5 as the next digit of our solution. 
Result so far: 5.0
Subtract 105 from 121 to get 16.
Append the next digit (2) from the dividend to 16 and continue with: 162 / 21

Step 4:
The number 21 fits into 162 7 times, leaving a remainder of 15.
Write down 7 as next digit of the result. 
Result so far: 57.0
The remainder is 15 after subtracting 147 from 162.
Bring next digit (3) of the dividend behind the 15 and repeat the process: 153 / 21

On to step 5:
When dividing 153 by 21, we get 7 with a remainder of 6.
The next digit of our result is 7. 
Result so far: 577.0
The remainder is 6 after subtracting 147 from 153.
Fetch the next digit (4) from the dividend, attach it to 6 and continue: 64 / 21

Step 6:
The number 21 fits into 64 3 times, leaving a remainder of 1.
Record the quotient 3 as the next digit in the result. 
Result so far: 5773.0
If we take 63 away from 64, we end up with 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 7:
21 goes into 10 0 times with a remainder of 10.
Record the quotient 0 as the next digit in the result. 
Result so far: 5773.0
Deduct 0 from 10 and we're left 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.

Let's proceed to step 8:
21 goes into 100 4 times with a remainder of 16.
Record the quotient 4 as the next digit in the result. 
Result so far: 5773.04
If we subtract 84 from 100, we 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.

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: 5773.047
The remainder is 13 after subtracting 147 from 160.
Since there are no more digits in the dividend, we add a zero to the remainder making it 130, and continue the process.

Going ahead to step 10:
130 divided by 21 is 6 with a remainder of 4.
Record the quotient 6 as the next digit in the result. 
Result so far: 5773.0476
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.

Going ahead to step 11:
The number 21 fits into 40 1 times, leaving a remainder of 19.
The next digit of our result is 1. 
Result so far: 5773.04761
Subtract 21 from 40 to 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:
21 goes into 190 9 times with a remainder of 1.
The number 9 becomes the next digit in our result. 
Result so far: 5773.047619
If we subtract 189 from 190, 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 13:
21 can be fit into 10 0 times, resulting in a remainder of 10.
Write down 0 as next digit of the result. 
Result so far: 5773.047619
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.

Step 14:
21 can be fit into 100 4 times, resulting in a remainder of 16.
Record the quotient 4 as the next digit in the result. 
Result so far: 5773.04761904
The remainder is 16 after subtracting 84 from 100.
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 5773.04761904 and a remainder of 1.6e-08.