We're dividing 73998 by 21 
Our goal is to divide 73998 by 21.

Going ahead to step 1:
21 goes into 7 0 times with a remainder of 7.
Use 0 as the next digit of our solution. 
Result so far: 0.0
The remainder is 7 after subtracting 0 from 7.
Grab the next digit (3) from the dividend, add it to 7, then carry on: 73 / 21

On to step 2:
73 divided by 21 is 3 with a remainder of 10.
Write down 3 as next digit of the result. 
Result so far: 3.0
The remainder is 10 after subtracting 63 from 73.
Take the next digit (9) from the dividend and append it to 10, then repeat: 109 / 21

Going ahead to step 3:
The number 21 fits into 109 5 times, leaving a remainder of 4.
Use 5 as the next digit of our solution. 
Result so far: 35.0
If we subtract 105 from 109, we get 4.
Take the next digit (9) from the dividend and append it to 4, then repeat: 49 / 21

Moving on to step 4:
49 divided by 21 is 2 with a remainder of 7.
Record the quotient 2 as the next digit in the result. 
Result so far: 352.0
The remainder is 7 after subtracting 42 from 49.
Include the next digit (8) from the dividend after 7, then repeat: 78 / 21

Moving on to step 5:
21 can be fit into 78 3 times, resulting in a remainder of 15.
Use 3 as the next digit of our solution. 
Result so far: 3523.0
If we take 63 away from 78, we end up with 15.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

Advancing to step 6:
150 divided by 21 is 7 with a remainder of 3.
The next digit of our result is 7. 
Result so far: 3523.7
Deduct 147 from 150 and we're left with 3.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

Going ahead to step 7:
If we divide 30 by 21, we get 1 and a remainder of 9.
The next digit of our result is 1. 
Result so far: 3523.71
The remainder is 9 after subtracting 21 from 30.
Since there are no more digits in the dividend, we add a zero to the remainder making it 90, and continue the process.

On to step 8:
21 goes into 90 4 times with a remainder of 6.
Use 4 as the next digit of our solution. 
Result so far: 3523.714
Subtract 84 from 90 to get 6.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

Moving on to step 9:
21 can be fit into 60 2 times, resulting in a remainder of 18.
Write down 2 as next digit of the result. 
Result so far: 3523.7142
Subtracting 42 from 60 leaves us with 18.
Since there are no more digits in the dividend, we add a zero to the remainder making it 180, and continue the process.

On to step 10:
21 can be fit into 180 8 times, resulting in a remainder of 12.
Put 8 as the next digit of the answer. 
Result so far: 3523.71428
If we subtract 168 from 180, we get 12.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

Advancing to step 11:
If we divide 120 by 21, we get 5 and a remainder of 15.
Record the quotient 5 as the next digit in the result. 
Result so far: 3523.714285
Deduct 105 from 120 and we're left with 15.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

Let's proceed to step 12:
The number 21 fits into 150 7 times, leaving a remainder of 3.
Use 7 as the next digit of our solution. 
Result so far: 3523.7142857
If we take 147 away from 150, we end up with 3.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

Moving on to step 13:
When dividing 30 by 21, we get 1 with a remainder of 9.
Write down 1 as next digit of the result. 
Result so far: 3523.71428571
If we subtract 21 from 30, we get 9.
Since there are no more digits in the dividend, we add a zero to the remainder making it 90, and continue the process.

After the division, we end up with 3523.71428571 and a remainder of 9e-09.