Let's divide 18001 by 21
We want to figure out the number of times 18001 can be divided by 21.

Let's proceed to step 1:
If we divide 1 by 21, we get 0 and a remainder of 1.
Write down 0 as next digit of the result. 
Result so far: 0.0
Deduct 0 from 1 and we're left with 1.
Append the next digit (8) from the dividend to 1 and continue with: 18 / 21

Step 2:
21 can be fit into 18 0 times, resulting in a remainder of 18.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we subtract 0 from 18, we get 18.
Fetch the next digit (0) from the dividend, attach it to 18 and continue: 180 / 21

Step 3:
21 can be fit into 180 8 times, resulting in a remainder of 12.
Record the quotient 8 as the next digit in the result. 
Result so far: 8.0
If we take 168 away from 180, we end up with 12.
Append the next digit (0) from the dividend to 12 and continue with: 120 / 21

Let's proceed to step 4:
120 divided by 21 is 5 with a remainder of 15.
The next digit of our result is 5. 
Result so far: 85.0
The remainder is 15 after subtracting 105 from 120.
Append the next digit (1) from the dividend to 15 and continue with: 151 / 21

Let's proceed to step 5:
If we divide 151 by 21, we get 7 and a remainder of 4.
The number 7 becomes the next digit in our result. 
Result so far: 857.0
Subtracting 147 from 151 leaves us with 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Moving on to step 6:
21 can be fit into 40 1 times, resulting in a remainder of 19.
Use 1 as the next digit of our solution. 
Result so far: 857.1
If we subtract 21 from 40, we 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.

On to step 7:
21 goes into 190 9 times with a remainder of 1.
Write down 9 as next digit of the result. 
Result so far: 857.19
Subtracting 189 from 190 leaves us 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.

Step 8:
The number 21 fits into 10 0 times, leaving a remainder of 10.
Record the quotient 0 as the next digit in the result. 
Result so far: 857.19
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.

Advancing to step 9:
21 goes into 100 4 times with a remainder of 16.
Use 4 as the next digit of our solution. 
Result so far: 857.1904
Subtracting 84 from 100 leaves us 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.

Let's proceed to step 10:
160 divided by 21 is 7 with a remainder of 13.
Record the quotient 7 as the next digit in the result. 
Result so far: 857.19047
If we take 147 away from 160, we end up with 13.
Since there are no more digits in the dividend, we add a zero to the remainder making it 130, and continue the process.

Let's proceed to step 11:
21 can be fit into 130 6 times, resulting in a remainder of 4.
Write down 6 as next digit of the result. 
Result so far: 857.190476
Subtracting 126 from 130 leaves us with 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Let's proceed to step 12:
40 divided by 21 is 1 with a remainder of 19.
The number 1 becomes the next digit in our result. 
Result so far: 857.1904761
If we subtract 21 from 40, we 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.

Advancing to step 13:
21 goes into 190 9 times with a remainder of 1.
Write down 9 as next digit of the result. 
Result so far: 857.19047619
If we take 189 away from 190, 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.

The final outcome is 857.19047619, with a leftover of 1e-09.