8644211 ÷ 864 
We want to figure out the number of times 8644211 can be divided by 864.

Moving on to step 1:
864 goes into 8 0 times with a remainder of 8.
The next digit of our result is 0. 
Result so far: 0.0
Deduct 0 from 8 and we're left with 8.
Take the next digit (6) from the dividend and append it to 8, then repeat: 86 / 864

Going ahead to step 2:
When dividing 86 by 864, we get 0 with a remainder of 86.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtracting 0 from 86 leaves us with 86.
Fetch the next digit (4) from the dividend, attach it to 86 and continue: 864 / 864

Moving on to step 3:
864 goes into 864 1 times with a remainder of 0.
Use 1 as the next digit of our solution. 
Result so far: 1.0
Subtracting 864 from 864 leaves us with 0.
Bring next digit (4) of the dividend behind the 0 and repeat the process: 4 / 864

Step 4:
If we divide 4 by 864, we get 0 and a remainder of 4.
Put 0 as the next digit of the answer. 
Result so far: 10.0
Deduct 0 from 4 and we're left with 4.
Grab the next digit (2) from the dividend, add it to 4, then carry on: 42 / 864

Going ahead to step 5:
864 goes into 42 0 times with a remainder of 42.
Use 0 as the next digit of our solution. 
Result so far: 100.0
Subtract 0 from 42 to get 42.
Grab the next digit (1) from the dividend, add it to 42, then carry on: 421 / 864

Let's proceed to step 6:
864 can be fit into 421 0 times, resulting in a remainder of 421.
Record the quotient 0 as the next digit in the result. 
Result so far: 1000.0
If we subtract 0 from 421, we get 421.
Take the next digit (1) from the dividend and append it to 421, then repeat: 4211 / 864

Going ahead to step 7:
If we divide 4211 by 864, we get 4 and a remainder of 755.
Use 4 as the next digit of our solution. 
Result so far: 10004.0
The remainder is 755 after subtracting 3456 from 4211.
Since there are no more digits in the dividend, we add a zero to the remainder making it 7550, and continue the process.

Step 8:
The number 864 fits into 7550 8 times, leaving a remainder of 638.
Record the quotient 8 as the next digit in the result. 
Result so far: 10004.8
If we take 6912 away from 7550, we end up with 638.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6380, and continue the process.

Let's proceed to step 9:
864 can be fit into 6380 7 times, resulting in a remainder of 332.
Record the quotient 7 as the next digit in the result. 
Result so far: 10004.87
Deduct 6048 from 6380 and we're left with 332.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3320, and continue the process.

Going ahead to step 10:
When dividing 3320 by 864, we get 3 with a remainder of 728.
Use 3 as the next digit of our solution. 
Result so far: 10004.873
Subtracting 2592 from 3320 leaves us with 728.
Since there are no more digits in the dividend, we add a zero to the remainder making it 7280, and continue the process.

Advancing to step 11:
When dividing 7280 by 864, we get 8 with a remainder of 368.
Use 8 as the next digit of our solution. 
Result so far: 10004.8738
Subtracting 6912 from 7280 leaves us with 368.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3680, and continue the process.

Going ahead to step 12:
864 goes into 3680 4 times with a remainder of 224.
Put 4 as the next digit of the answer. 
Result so far: 10004.87384
Deduct 3456 from 3680 and we're left with 224.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2240, and continue the process.

Moving on to step 13:
2240 divided by 864 is 2 with a remainder of 512.
Write down 2 as next digit of the result. 
Result so far: 10004.873842
If we take 1728 away from 2240, we end up with 512.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5120, and continue the process.

Let's proceed to step 14:
864 can be fit into 5120 5 times, resulting in a remainder of 800.
Record the quotient 5 as the next digit in the result. 
Result so far: 10004.8738425
If we subtract 4320 from 5120, we get 800.
Since there are no more digits in the dividend, we add a zero to the remainder making it 8000, and continue the process.

Going ahead to step 15:
When dividing 8000 by 864, we get 9 with a remainder of 224.
The number 9 becomes the next digit in our result. 
Result so far: 10004.87384259
Subtracting 7776 from 8000 leaves us with 224.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2240, and continue the process.

The final outcome is 10004.87384259, with a leftover of 2.24e-07.