Let's divide 100377 by 21
Our goal is to divide 100377 by 21.

Step 1:
21 can be fit into 1 0 times, resulting in a remainder of 1.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtracting 0 from 1 leaves us with 1.
Take the next digit (0) from the dividend and append it to 1, then repeat: 10 / 21

Going ahead to step 2:
When dividing 10 by 21, we get 0 with a remainder of 10.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we take 0 away from 10, we end up with 10.
Grab the next digit (0) from the dividend, add it to 10, then carry on: 100 / 21

Advancing to step 3:
The number 21 fits into 100 4 times, leaving a remainder of 16.
Use 4 as the next digit of our solution. 
Result so far: 4.0
The remainder is 16 after subtracting 84 from 100.
Fetch the next digit (3) from the dividend, attach it to 16 and continue: 163 / 21

Advancing to step 4:
The number 21 fits into 163 7 times, leaving a remainder of 16.
Use 7 as the next digit of our solution. 
Result so far: 47.0
If we take 147 away from 163, we end up with 16.
Include the next digit (7) from the dividend after 16, then repeat: 167 / 21

Step 5:
When dividing 167 by 21, we get 7 with a remainder of 20.
Put 7 as the next digit of the answer. 
Result so far: 477.0
Subtracting 147 from 167 leaves us with 20.
Include the next digit (7) from the dividend after 20, then repeat: 207 / 21

Moving on to step 6:
21 goes into 207 9 times with a remainder of 18.
Record the quotient 9 as the next digit in the result. 
Result so far: 4779.0
Subtract 189 from 207 to get 18.
Since there are no more digits in the dividend, we add a zero to the remainder making it 180, and continue the process.

Let's proceed to step 7:
180 divided by 21 is 8 with a remainder of 12.
Use 8 as the next digit of our solution. 
Result so far: 4779.8
Deduct 168 from 180 and we're left with 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 8:
When dividing 120 by 21, we get 5 with a remainder of 15.
The next digit of our result is 5. 
Result so far: 4779.85
Subtracting 105 from 120 leaves us 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 9:
150 divided by 21 is 7 with a remainder of 3.
The number 7 becomes the next digit in our result. 
Result so far: 4779.857
Subtracting 147 from 150 leaves us 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.

On to step 10:
If we divide 30 by 21, we get 1 and a remainder of 9.
Put 1 as the next digit of the answer. 
Result so far: 4779.8571
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.

On to step 11:
If we divide 90 by 21, we get 4 and a remainder of 6.
Write down 4 as next digit of the result. 
Result so far: 4779.85714
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.

On to step 12:
When dividing 60 by 21, we get 2 with a remainder of 18.
Use 2 as the next digit of our solution. 
Result so far: 4779.857142
If we take 42 away from 60, we end up 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.

Step 13:
When dividing 180 by 21, we get 8 with a remainder of 12.
Record the quotient 8 as the next digit in the result. 
Result so far: 4779.8571428
The remainder is 12 after subtracting 168 from 180.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

Step 14:
When dividing 120 by 21, we get 5 with a remainder of 15.
The number 5 becomes the next digit in our result. 
Result so far: 4779.85714285
The remainder is 15 after subtracting 105 from 120.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

The final outcome is 4779.85714285, with a leftover of 1.5e-08.