We're dividing 90831921 by 648 
We're looking to find how many times 648 goes into 90831921.

Moving on to step 1:
When dividing 9 by 648, we get 0 with a remainder of 9.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
If we take 0 away from 9, we end up with 9.
Include the next digit (0) from the dividend after 9, then repeat: 90 / 648

Advancing to step 2:
The number 648 fits into 90 0 times, leaving a remainder of 90.
Put 0 as the next digit of the answer. 
Result so far: 0.0
The remainder is 90 after subtracting 0 from 90.
Take the next digit (8) from the dividend and append it to 90, then repeat: 908 / 648

Advancing to step 3:
When dividing 908 by 648, we get 1 with a remainder of 260.
Use 1 as the next digit of our solution. 
Result so far: 1.0
Subtracting 648 from 908 leaves us with 260.
Grab the next digit (3) from the dividend, add it to 260, then carry on: 2603 / 648

Advancing to step 4:
648 can be fit into 2603 4 times, resulting in a remainder of 11.
Record the quotient 4 as the next digit in the result. 
Result so far: 14.0
If we take 2592 away from 2603, we end up with 11.
Append the next digit (1) from the dividend to 11 and continue with: 111 / 648

Advancing to step 5:
When dividing 111 by 648, we get 0 with a remainder of 111.
The next digit of our result is 0. 
Result so far: 140.0
If we take 0 away from 111, we end up with 111.
Append the next digit (9) from the dividend to 111 and continue with: 1119 / 648

Step 6:
If we divide 1119 by 648, we get 1 and a remainder of 471.
The next digit of our result is 1. 
Result so far: 1401.0
Subtracting 648 from 1119 leaves us with 471.
Take the next digit (2) from the dividend and append it to 471, then repeat: 4712 / 648

Advancing to step 7:
If we divide 4712 by 648, we get 7 and a remainder of 176.
The next digit of our result is 7. 
Result so far: 14017.0
If we subtract 4536 from 4712, we get 176.
Append the next digit (1) from the dividend to 176 and continue with: 1761 / 648

Advancing to step 8:
1761 divided by 648 is 2 with a remainder of 465.
Put 2 as the next digit of the answer. 
Result so far: 140172.0
Subtracting 1296 from 1761 leaves us with 465.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4650, and continue the process.

Advancing to step 9:
The number 648 fits into 4650 7 times, leaving a remainder of 114.
Put 7 as the next digit of the answer. 
Result so far: 140172.7
Deduct 4536 from 4650 and we're left with 114.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1140, and continue the process.

On to step 10:
648 can be fit into 1140 1 times, resulting in a remainder of 492.
Put 1 as the next digit of the answer. 
Result so far: 140172.71
Deduct 648 from 1140 and we're left with 492.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4920, and continue the process.

Let's proceed to step 11:
648 can be fit into 4920 7 times, resulting in a remainder of 384.
Use 7 as the next digit of our solution. 
Result so far: 140172.717
Subtracting 4536 from 4920 leaves us with 384.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3840, and continue the process.

Step 12:
3840 divided by 648 is 5 with a remainder of 600.
Write down 5 as next digit of the result. 
Result so far: 140172.7175
If we take 3240 away from 3840, we end up with 600.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6000, and continue the process.

Advancing to step 13:
648 goes into 6000 9 times with a remainder of 168.
Put 9 as the next digit of the answer. 
Result so far: 140172.71759
Subtract 5832 from 6000 to get 168.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1680, and continue the process.

Going ahead to step 14:
1680 divided by 648 is 2 with a remainder of 384.
The next digit of our result is 2. 
Result so far: 140172.717592
Deduct 1296 from 1680 and we're left with 384.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3840, and continue the process.

Let's proceed to step 15:
If we divide 3840 by 648, we get 5 and a remainder of 600.
The next digit of our result is 5. 
Result so far: 140172.7175925
If we take 3240 away from 3840, we end up with 600.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6000, and continue the process.

Moving on to step 16:
When dividing 6000 by 648, we get 9 with a remainder of 168.
The number 9 becomes the next digit in our result. 
Result so far: 140172.71759259
Deduct 5832 from 6000 and we're left with 168.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1680, and continue the process.

The final result is 140172.71759259 with a remainder of 1.68e-07.