We look at the division of 84070255 by 21 
Let's see how many times 21 fits into 84070255.

Moving on to step 1:
8 divided by 21 is 0 with a remainder of 8.
Write down 0 as next digit of the result. 
Result so far: 0.0
If we subtract 0 from 8, we get 8.
Include the next digit (4) from the dividend after 8, then repeat: 84 / 21

Going ahead to step 2:
When dividing 84 by 21, we get 4 with a remainder of 0.
The next digit of our result is 4. 
Result so far: 4.0
Subtract 84 from 84 to get 0.
Include the next digit (0) from the dividend after 0, then repeat: 0 / 21

On to step 3:
If we divide 0 by 21, we get 0 and a remainder of 0.
Record the quotient 0 as the next digit in the result. 
Result so far: 40.0
The remainder is 0 after subtracting 0 from 0.
Fetch the next digit (7) from the dividend, attach it to 0 and continue: 7 / 21

Going ahead to step 4:
21 goes into 7 0 times with a remainder of 7.
Write down 0 as next digit of the result. 
Result so far: 400.0
Subtracting 0 from 7 leaves us with 7.
Include the next digit (0) from the dividend after 7, then repeat: 70 / 21

Let's proceed to step 5:
When dividing 70 by 21, we get 3 with a remainder of 7.
Put 3 as the next digit of the answer. 
Result so far: 4003.0
If we take 63 away from 70, we end up with 7.
Grab the next digit (2) from the dividend, add it to 7, then carry on: 72 / 21

Let's proceed to step 6:
21 goes into 72 3 times with a remainder of 9.
Write down 3 as next digit of the result. 
Result so far: 40033.0
Deduct 63 from 72 and we're left with 9.
Fetch the next digit (5) from the dividend, attach it to 9 and continue: 95 / 21

Step 7:
If we divide 95 by 21, we get 4 and a remainder of 11.
Put 4 as the next digit of the answer. 
Result so far: 400334.0
If we take 84 away from 95, we end up with 11.
Append the next digit (5) from the dividend to 11 and continue with: 115 / 21

Advancing to step 8:
If we divide 115 by 21, we get 5 and a remainder of 10.
The number 5 becomes the next digit in our result. 
Result so far: 4003345.0
The remainder is 10 after subtracting 105 from 115.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Going ahead to step 9:
21 can be fit into 100 4 times, resulting in a remainder of 16.
The next digit of our result is 4. 
Result so far: 4003345.4
If we take 84 away from 100, we end up 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.

On to step 10:
When dividing 160 by 21, we get 7 with a remainder of 13.
Write down 7 as next digit of the result. 
Result so far: 4003345.47
Deduct 147 from 160 and we're left 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:
When dividing 130 by 21, we get 6 with a remainder of 4.
The number 6 becomes the next digit in our result. 
Result so far: 4003345.476
Deduct 126 from 130 and we're left 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.

Going ahead to step 12:
The number 21 fits into 40 1 times, leaving a remainder of 19.
The next digit of our result is 1. 
Result so far: 4003345.4761
The remainder is 19 after subtracting 21 from 40.
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 13:
When dividing 190 by 21, we get 9 with a remainder of 1.
Record the quotient 9 as the next digit in the result. 
Result so far: 4003345.47619
Deduct 189 from 190 and we're left 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.

Advancing to step 14:
When dividing 10 by 21, we get 0 with a remainder of 10.
Record the quotient 0 as the next digit in the result. 
Result so far: 4003345.47619
Subtract 0 from 10 to get 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 15:
21 goes into 100 4 times with a remainder of 16.
Put 4 as the next digit of the answer. 
Result so far: 4003345.4761904
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 16:
If we divide 160 by 21, we get 7 and a remainder of 13.
The number 7 becomes the next digit in our result. 
Result so far: 4003345.47619047
Subtracting 147 from 160 leaves us 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.

The final result is 4003345.47619047 with a remainder of 1.3e-08.