83518049 ÷ 21 
Let's see how many times 21 fits into 83518049.

Step 1:
8 divided by 21 is 0 with a remainder of 8.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Deduct 0 from 8 and we're left with 8.
Take the next digit (3) from the dividend and append it to 8, then repeat: 83 / 21

Going ahead to step 2:
When dividing 83 by 21, we get 3 with a remainder of 20.
Record the quotient 3 as the next digit in the result. 
Result so far: 3.0
The remainder is 20 after subtracting 63 from 83.
Append the next digit (5) from the dividend to 20 and continue with: 205 / 21

Advancing to step 3:
When dividing 205 by 21, we get 9 with a remainder of 16.
Put 9 as the next digit of the answer. 
Result so far: 39.0
Subtracting 189 from 205 leaves us with 16.
Append the next digit (1) from the dividend to 16 and continue with: 161 / 21

Advancing to step 4:
The number 21 fits into 161 7 times, leaving a remainder of 14.
Record the quotient 7 as the next digit in the result. 
Result so far: 397.0
Subtract 147 from 161 to get 14.
Append the next digit (8) from the dividend to 14 and continue with: 148 / 21

Moving on to step 5:
If we divide 148 by 21, we get 7 and a remainder of 1.
The next digit of our result is 7. 
Result so far: 3977.0
If we take 147 away from 148, we end up with 1.
Grab the next digit (0) from the dividend, add it to 1, then carry on: 10 / 21

On to step 6:
The number 21 fits into 10 0 times, leaving a remainder of 10.
Put 0 as the next digit of the answer. 
Result so far: 39770.0
Deduct 0 from 10 and we're left with 10.
Fetch the next digit (4) from the dividend, attach it to 10 and continue: 104 / 21

Let's proceed to step 7:
21 goes into 104 4 times with a remainder of 20.
Record the quotient 4 as the next digit in the result. 
Result so far: 397704.0
Subtract 84 from 104 to get 20.
Grab the next digit (9) from the dividend, add it to 20, then carry on: 209 / 21

Step 8:
21 goes into 209 9 times with a remainder of 20.
Record the quotient 9 as the next digit in the result. 
Result so far: 3977049.0
The remainder is 20 after subtracting 189 from 209.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

On to step 9:
The number 21 fits into 200 9 times, leaving a remainder of 11.
The next digit of our result is 9. 
Result so far: 3977049.9
Subtract 189 from 200 to get 11.
Since there are no more digits in the dividend, we add a zero to the remainder making it 110, and continue the process.

Advancing to step 10:
21 goes into 110 5 times with a remainder of 5.
The next digit of our result is 5. 
Result so far: 3977049.95
If we take 105 away from 110, we end up with 5.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

Going ahead to step 11:
21 goes into 50 2 times with a remainder of 8.
Record the quotient 2 as the next digit in the result. 
Result so far: 3977049.952
The remainder is 8 after subtracting 42 from 50.
Since there are no more digits in the dividend, we add a zero to the remainder making it 80, and continue the process.

Going ahead to step 12:
80 divided by 21 is 3 with a remainder of 17.
Record the quotient 3 as the next digit in the result. 
Result so far: 3977049.9523
Subtract 63 from 80 to get 17.
Since there are no more digits in the dividend, we add a zero to the remainder making it 170, and continue the process.

On to step 13:
21 goes into 170 8 times with a remainder of 2.
Record the quotient 8 as the next digit in the result. 
Result so far: 3977049.95238
Deduct 168 from 170 and we're left with 2.
Since there are no more digits in the dividend, we add a zero to the remainder making it 20, and continue the process.

On to step 14:
20 divided by 21 is 0 with a remainder of 20.
Put 0 as the next digit of the answer. 
Result so far: 3977049.95238
Subtract 0 from 20 to get 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

Advancing to step 15:
21 goes into 200 9 times with a remainder of 11.
Put 9 as the next digit of the answer. 
Result so far: 3977049.9523809
Subtract 189 from 200 to get 11.
Since there are no more digits in the dividend, we add a zero to the remainder making it 110, and continue the process.

Let's proceed to step 16:
If we divide 110 by 21, we get 5 and a remainder of 5.
Write down 5 as next digit of the result. 
Result so far: 3977049.95238095
If we subtract 105 from 110, we get 5.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

In conclusion, the division gives 3977049.95238095 with a balance of 5e-09.