8721321 ÷ 837 
Our goal is to divide 8721321 by 837.

On to step 1:
When dividing 8 by 837, we get 0 with a remainder of 8.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we take 0 away from 8, we end up with 8.
Grab the next digit (7) from the dividend, add it to 8, then carry on: 87 / 837

Going ahead to step 2:
837 goes into 87 0 times with a remainder of 87.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Subtract 0 from 87 to get 87.
Take the next digit (2) from the dividend and append it to 87, then repeat: 872 / 837

Moving on to step 3:
837 goes into 872 1 times with a remainder of 35.
Put 1 as the next digit of the answer. 
Result so far: 1.0
Subtracting 837 from 872 leaves us with 35.
Grab the next digit (1) from the dividend, add it to 35, then carry on: 351 / 837

On to step 4:
837 goes into 351 0 times with a remainder of 351.
The next digit of our result is 0. 
Result so far: 10.0
If we subtract 0 from 351, we get 351.
Append the next digit (3) from the dividend to 351 and continue with: 3513 / 837

Going ahead to step 5:
When dividing 3513 by 837, we get 4 with a remainder of 165.
Record the quotient 4 as the next digit in the result. 
Result so far: 104.0
Deduct 3348 from 3513 and we're left with 165.
Append the next digit (2) from the dividend to 165 and continue with: 1652 / 837

Moving on to step 6:
1652 divided by 837 is 1 with a remainder of 815.
The number 1 becomes the next digit in our result. 
Result so far: 1041.0
If we subtract 837 from 1652, we get 815.
Fetch the next digit (1) from the dividend, attach it to 815 and continue: 8151 / 837

Going ahead to step 7:
8151 divided by 837 is 9 with a remainder of 618.
The number 9 becomes the next digit in our result. 
Result so far: 10419.0
If we take 7533 away from 8151, we end up with 618.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6180, and continue the process.

Going ahead to step 8:
If we divide 6180 by 837, we get 7 and a remainder of 321.
The next digit of our result is 7. 
Result so far: 10419.7
Subtracting 5859 from 6180 leaves us with 321.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3210, and continue the process.

Moving on to step 9:
837 goes into 3210 3 times with a remainder of 699.
Use 3 as the next digit of our solution. 
Result so far: 10419.73
Subtracting 2511 from 3210 leaves us with 699.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6990, and continue the process.

Let's proceed to step 10:
The number 837 fits into 6990 8 times, leaving a remainder of 294.
Put 8 as the next digit of the answer. 
Result so far: 10419.738
If we subtract 6696 from 6990, we get 294.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2940, and continue the process.

Advancing to step 11:
837 goes into 2940 3 times with a remainder of 429.
The next digit of our result is 3. 
Result so far: 10419.7383
Subtract 2511 from 2940 to get 429.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4290, and continue the process.

On to step 12:
When dividing 4290 by 837, we get 5 with a remainder of 105.
The next digit of our result is 5. 
Result so far: 10419.73835
If we take 4185 away from 4290, we end up with 105.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1050, and continue the process.

Advancing to step 13:
837 goes into 1050 1 times with a remainder of 213.
Record the quotient 1 as the next digit in the result. 
Result so far: 10419.738351
The remainder is 213 after subtracting 837 from 1050.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2130, and continue the process.

Step 14:
The number 837 fits into 2130 2 times, leaving a remainder of 456.
Record the quotient 2 as the next digit in the result. 
Result so far: 10419.7383512
Subtracting 1674 from 2130 leaves us with 456.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4560, and continue the process.

Going ahead to step 15:
If we divide 4560 by 837, we get 5 and a remainder of 375.
Record the quotient 5 as the next digit in the result. 
Result so far: 10419.73835125
Subtracting 4185 from 4560 leaves us with 375.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3750, and continue the process.

The final outcome is 10419.73835125, with a leftover of 3.75e-07.